This invention relates to novel methods for affecting, controlling and/or directing various reactions and/or reaction pathways or systems by exposing one or more components in a fuel cell reaction system to at least one spectral energy pattern. In a first aspect of the invention, at least one spectral energy pattern can be applied to a fuel cell reaction system. In a second aspect of the invention, at least one spectral energy conditioning pattern can be applied to a conditioning reaction system. The spectral energy conditioning pattern can, for example, be applied at a separate location from the reaction vessel (e.g., in a conditioning reaction vessel) or can be applied in (or to) the reaction vessel, but prior to other reaction system participants being introduced into the reaction vessel.

Electrochemistry can be summarized as two simple and mirrored concepts: (1) the passage of an electrical current to cause chemical transformation of matter; and (2) the chemical transformation of matter to cause the passage of an electrical current.
Electrochemistry involves numerous oxidation and reduction reactions at or near anodes, cathodes and electrolytes in various electrochemical and electrolytic cells. The specific reactions can occur by applying a current to various chemical reactants contained in a system to achieve a desired chemical species (e.g., electrolysis) or conversely, chemical reactions can result in the production of electricity (e.g., electrochemical reactions). In certain systems both electrolytic and electrochemical reactions occur (e.g., rechargeable cells or rechargeable batteries). Oxidation reactions are those reactions which lose electrons, whereas reduction reactions are those reactions which gain electrons. Oxidation and reduction reactions occur in many chemical systems. For example, the rusting of metals, photosynthesis in the leaves of green plants, the conversion of foods to energy in the body, the generation of current from batteries and fuel cells, etc., are all examples of chemical changes that involve the transfer of electrons from one chemical species to another. When such reactions result in electrons flowing through a wire or when the flow of electrons causes a particular reduction reaction to occur, the processes are generally referred to as electrochemical reactions. Whereas the study and/or application of these electrochemical reactions is often referred to as electrochemistry.
The applications of electrochemistry are widespread, as discussed above. Additionally, electrical measurements are used to monitor chemical reactions in a wide variety of reactions, including those reactions occurring in an element as small as a living cell. Further, numerous important chemicals are manufactured by electrochemical means. In addition, electrochemistry is used to form a variety of important metals (e.g., aluminum and magnesium). Still further, electrochemistry is used in corrosion protection, brine electrolysis, electrocrystallization, electroforming, electrolyte pickling, electrometallurgy, electroplating, electrorefining, electrowinning, galvanizing, photoelectrochemistry; photoelectrosynthesis and sonoelectrochemistry.
Many reactions that occur in the aforementioned systems appear to involve a shifting of electron density from one atom to another. Collectively, this shifting of electron density is referred to as oxidation/reduction reactions or more simply, redox reactions. The term "oxidation" refers to the loss of electrons by one reactant and the term "reduction" refers to the gain of electrons by another. Oxidation and reduction typically occur together. In particular, if one substance is oxidized, another substance is typically reduced. Otherwise, electrons would be a product of a reaction, and this has not been observed in these reactions. During a redox reaction the substance that accepts the electrons that another substance loses is known as an "oxidizing agent", because it helps something else to be oxidized. Moreover, the substance that supplies electrons is termed the "reducing agent" because it helps something else to be reduced.
There is known to the art a variety of different fuel cells which function generally in a similar manner and which use various electrochemical reactions. In general, in each of the fuel cells, an electrochemical reaction occurs at each of the anode and the cathode whereby, typically, one or more atomic species and/or molecules may donate electrons at the anode and become an ionic species. Donated electrons become involved in the flow of current from the anode to the cathode. The created ionic species is caused to flow through an electrolyte and toward the cathode and typically reacts, through a reduction half-reaction with another species at, or near the cathode. The names given to the different fuel cells are a function of the different electrolytes used to conduct ions in the fuel cell. In particular, the following is a list of some of the better known fuel cells: proton exchange membrane fuel cells or polymer exchange membrane fuel cells ("PEMFC"); phosphoric acid fuel cells ("PAFC"); molten carbonate fuel cells ("MCFC"); solid oxide fuel cells ("SOFC"); alkaline fuel cells ("AFC"); direct methanol fuel cells; regenerative fuel cells; zinc-air fuel cells; and protonic-ceramic fuel cells. The names of the different fuel cells relate directly to the electrolytes present between the anode and the cathode.
A fuel cell, similar to a battery, is an electrochemical energy conversion device. Different fuel cells utilize different sources of fuel, but one of the most common sources of fuel for fuel cells is hydrogen. Hydrogen is involved, directly or indirectly, in at least a portion of one reaction at the anode or the cathode in each of the fuel cells listed above. For example, in each of the PEMFC's and PAFC's, hydrogen, typically, in the form of a gas, is used as a fuel and reacts at an anode to become a hydrogen ion (or proton) by the use of a platinum catalyst on, in and/or near the anode, which anode is in contact with a polymer electrolyte membrane. In particular, the reaction at the anode is known as a half-reaction (i.e., there are two general sets of overall reactions in a fuel cell, namely, those reactions occurring at or near the anode; and those reactions occurring at or near the cathode). The half-reaction at the anode in each of PEMFC's and PAFC's is as follows:2H2→4H++4e−.Accordingly, the half-reaction at the anode in the hydrogen fueled fuel cells results in the production of hydrogen ions and electrons. The produced hydrogen ions or protons are caused to migrate through an electrolyte (e.g., a polymer membrane in PEMFC's and liquid phosphoric acid in PAFC's), and are directed toward the cathode side of the fuel cell.
At or near the cathode, a typical reaction occurring in a hydrogen-fueled fuel cell (e.g., a PEMFC or a PAFC) involves the hydrogen ions being combined with oxygen (e.g., oxygen supplied from the air or pure oxygen) as well as free electrons that have been caused to flow from the anode to the cathode. In particular, the half-reaction occurring at the cathode in PEMFC's and PAFC's is known as a reduction reaction and occurs generally as follows:O2+4H++4e−→2H2O.
Accordingly, the overall fuel cell reaction (i.e., that reaction which defines the starting components and finishing components), is as follows:2H2+O2→2H2O.
The actual half-reactions that occur at each of the anode and cathode are more complex than those listed above (e.g., various intermediates are also involved) however, the equations are representative of the overall reactions. The total potential or voltage created in a fuel cell is the sum of the voltages created by each of the half-reactions, in particular, the oxidation half-reaction at the anode produces a certain voltage potential and the reduction half-reaction at the cathode produces another voltage potential. These two voltage potentials can be summed to obtain the total voltage of the fuel cell. For example, in a typical PEM fuel cell utilizing hydrogen as a fuel, the voltage from a single cell is about 0.7 Volts. In order to obtain higher voltages, stacks of fuel cells are created and such fuel cells are typically wired in series to create the stack. Accordingly, such stacks can result in significant voltages and currents.
The various electrochemical reactions that occur at each of the anode and the cathode may need to be catalyzed by a physical catalyst. A catalyst that has found a wide abundance of usage is a platinum catalyst. The reason that catalysts are utilized in some fuel cells, typically, is to obtain reaction rates that are acceptable at somewhat lower temperatures (e.g., room temperature to a few hundred degrees Celsius). In other words, in the absence of a catalyst, one or more of the half-reactions occurring at the anode and/or cathode are, typically, too slow to result in the production of enough electrons to achieve any meaningful results. While many reactions increase with increasing temperature, high operating temperatures are not possible to achieve in many of the fuel cells due to the materials that are utilized (e.g., water, low temperature polymers, etc.).
For those fuel cells that require physical catalysts, the prior art is replete with attempts to make more efficient use of the somewhat expensive catalysts, such as platinum, by, for example, reducing the amount of platinum required, while still maintaining acceptable reaction rates. Further, the prior art admits that a large amount of knowledge needs to be gained in understanding how to utilize existing catalysts better, as well as discovering new catalysts that may be better suited for optimizing various electrochemical reactions. In particular, the prior are does not understand the variety of complexities associated with the membrane/electrode assembly or MEA. Optimization of membrane/electrode assemblies, especially when catalysts are included, is a major goal of the prior art.
The prior art further discloses various electrolyte materials for use in various MEA assemblies that are utilized for the transport of ions through the various electrolytes. The prior art continues to search for new materials and/or methods which can enhance the operation of various electrolyte materials, as well as interactions between electrolyte materials and electrodes and/or catalysts, and thus improve the performance of the various fuel cells.
Still further, the electrodes used in fuel cells have also been a large focus in the prior art. In particular, electrodes are quite porous so as to result in a large amount of surface area in the electrodes so that, for example: (1) catalyzed reactions can occur in a much greater surface area and thus, can occur at rates that are acceptable for electron flow (i.e., rendering fuel cells commercially feasible due to acceptable amounts of current between the anode and the cathode); and (2) so that reactants and/or reaction products can readily flow therethrough (i.e., so that such reactants and/or reaction products can communicate with the electrolyte). In some cases, such electrodes exist as independent solid members, whereas in other cases electrodes may be physically placed on at least a portion of an electrolyte (e.g., electrodes may be screen printed on or painted on certain electrolyte materials).
In addition to the electrodes (i.e., the anode and the cathode), and the electrolyte which is positioned therebetween, fuel cells require some type of mechanism for permitting, for example, gaseous fuel to be flowed to the anode, as well as gaseous air or oxygen flowing, typically, to the cathode. Thus, for example, in PEMFC's, various passageways or flow fields or flow channels are created which permit the flow of, for example, gases to the electrodes. Numerous such structures exist in the prior art in combination with various backing plates, control valves and pressure regulators, all of which are all well known, but are continually being modified in an attempt to achieve more acceptable performance in the various fuel cell systems.
In every fuel cell system, there are a variety of chemical reactions that need to occur in order to produce ion flow and electron flow. Many of these reactions are admittedly not well understood, but are thought to be essential to the desirable functioning of a fuel cell. However, many of these reactions do not occur at a fast enough rate to render fuel cells commercially desirable for numerous applications. Moreover, many half-reactions may occur, for example, at an anode at an acceptable rate, but other half-reactions at a cathode may slow down the overall output of a fuel cell. Accordingly, in some fuel cell systems, an increase in reaction rate at either the anode or the cathode could have significant positive performance results for the fuel cell.
As discussed above, much focus in the prior art has been placed on minimizing the amount of, for example, catalysts needed in a fuel cell because, for example, many such catalysts are relatively expensive, difficult to obtain, difficult to manufacture, etc. These, as well, as various other limitations, have prevented fuel cells from becoming widely accepted and utilized. However, the potential for successful utilization of fuel cells remains great.
In addition to the various reactions that occur within the fuel cell reaction system per se (i.e., as defined herein), the prior art has utilized various different techniques or technologies for delivering various fuels to the fuel cell. In particular, hydrogen has received an enormous amount of attention as a desirable fuel source for fuel cells. Known sources of hydrogen include, for example, hydrogen gases, precursors to hydrogen such as gasoline, diesel fuel, methanol, etc., as well as various solids such as one or more known metal hydrides. From a chemistry standpoint, the utilization of pure hydrogen provides the most simple form of fuel for fuel cells. However, gaseous hydrogen sources have the limitation that highly pressurized hydrogen needs to be available and in many cases portable, which could result in certain difficulties. For example, if fuel cells are to achieve desirable acceptance in automobiles, then some type of nationwide dispensing mechanism for hydrogen will most likely be required.
With regard to liquid precursors to hydrogen, such as those mentioned above, the hydrogen needs to go through some type of a catalyzed reformation process so that hydrogen can be released from the various liquids. This process has certain advantages in that infrastructures exist around most of the world for dispensing liquids such as gasoline, diesel fuel, methanol, etc, but the use of such liquids has drawbacks in that additional reactions need to occur to form an acceptably pure fuel for inputting into fuel cells. In these cases, additional equipment needs to be provided for the reformation reactions. In the case of moving vehicles, the extra equipment means extra, and usually undesirable, weight. Further, various undesirable by-products (e.g., carbon monoxide) may also form during the reformation reaction and such undesirable by-products may adversely interfere with certain electrochemical reactions including the reactions involving physical catalysts which have been added to the fuel cell reaction system (e.g., CO can block the activity of platinum catalyst sites thus reducing the efficiency of oxidation and/or reduction reactions in a fuel system). Accordingly, the prior art would benefit from a process which could reactivate those catalyst sites that become at least partially blocked during the functioning of the fuel cell.
The prior art has also focussed some attention on providing hydrogen in solid form by, for example, causing hydrogen to be absorbed into various metals. In particular, various metal hydrides have been formulated by the prior art, but have yet to be optimized. In this regard, much mystery still surrounds acceptable metals or metal alloys and the ability of the metal and/or metal alloys to accept hydrogen into their structure. Certain such metals such as palladium have achieved particular attention, but metal alloys such as titanium, nickel, vanadium, zirconium, chromium, cobalt and iron, etc., have also come into favor (e.g., LiN15 is capable of storing six hydrogen atoms per unit cell to form LiN15H6). The desirability of storing hydrogen in a solid form is that much more hydrogen can, in theory, be made available as fuel for the fuel cell in a similar amount of space relative to gaseous sources of hydrogen. However, the additional weight of the metal needs to be taken account and, thus, the storage of hydrogen needs to be efficiently achieved in order for solid storage of hydrogen to be feasible in, for example, mobile fuel cell applications.
Accordingly, it is clear from all the above, that a variety of electrochemical reactions are important in every fuel cell reaction system in order to achieve a desirably functioning fuel cell. Focus upon these various electrochemical reactions, as well as all of the chemical species and/or physical species involved in the reactions, is important.
The various reactions that occur in the aforementioned electrochemical systems are driven by energy. The energy comes primarily in two different forms: chemical and electrical. There are many other forms of energy that drive chemical transformation, however, including thermal, mechanical, acoustic, and electromagnetic. Various features of each type of energy are thought to contribute in different ways to the driving of chemical reactions. Irrespective of the type of energy involved, chemical reactions and transformations are undeniably and inextricably intertwined with the transfer and combination of energy. An understanding of energy is, therefore, vital to an understanding of chemical reactions, including electrochemical reactions.
A chemical reaction can be controlled and/or directed either by the addition of energy to the reaction medium in the form of thermal, mechanical, acoustic, electrical, magnetic, and/or electromagnetic energy or by means of transferring energy through a physical catalyst. These methods are traditionally not that energy efficient and can produce, for example, either unwanted by-products, decomposition of required transients, and/or intermediates and/or activated complexes and/or insufficient quantities of preferred products of a reaction.
It has been generally believed that chemical reactions occur as a result of collisions between reacting molecules. In terms of the collision theory of chemical kinetics, it has been expected that the rate of a reaction is directly proportional to the number of the molecular collisions per second:rate α number of collisions/secThis simple relationship has been used to explain the dependence of reaction rates on concentration. Additionally, with few exceptions, reaction rates have been believed to increase with increasing temperature because of increased collisions.
The dependence of the rate constant k of a reaction can be expressed by the following equation, known as the Arrhenius equation:k=Ae−Ea/RT where Eα is the activation energy of the reaction which is the minimum amount of energy required to initiate a chemical reaction, R is the gas constant, T is the absolute temperature and e is the base of the natural logarithm scale. The quantity A represents the collision rate and shows that the rate constant is directly proportional to A and, therefore, to the collision rate. Furthermore, because of the minus sign associated with the exponent Eα/RT, the rate constant decreases with increasing activation energy and increases with increasing temperature.
Normally, only a small fraction of the colliding molecules, typically the fastest-moving ones, have enough kinetic energy to exceed the activation energy, therefore, the increase in the rate constant k has been explained with the temperature increase. Since more high-energy molecules are present at a higher temperature, the rate of product formation is also greater at the higher temperature. But, with increased temperatures there are a number of problems which can be introduced into the cell reaction system. With thermal excitation other competing processes, such as bond rupture, may occur before the desired energy state can be reached. Also, there are a number of decomposition products which often produce fragments that are extremely reactive, but they can be so short-lived because of their thermodynamic instability, that a preferred reaction may be dampened.
In electrochemical reactions, it is generally believed that chemical transformations occur as the result of the passage of an electrical current, or conversely that a chemical reaction produces an electrical current. In this regard, electrochemistry involves the science of ionically conducting solutions, as well as the science of electrically charged interfaces. There are four important aspects of ionically conducting solutions: (1) ion interactions with the solvent; (2) ion interactions with other ions (either of the same or different species); (3) movement of ions in solutions; and (4) ionic liquids or "pure electrolytes"
Electrodics, the same science of electrically charged interfaces, involves the transfer of charge across solid-solution interfaces and interfacial regions. Electrodics thus involves the transfer of electrical charge between two phases of matter. These phases can exist on surfaces of materials not customarily thought of as solid-solution interfaces. Corrosion is a good example of this, wherein a material is covered by a thick invisible film of moisture. Atoms on the surface of the material leave the material and dissolve into the ion-containing film of moisture. Thus, in electrochemistry, the familiar kinetic catalysts of chemical reactions by molecules and atoms colliding with each other is replaced by species colliding with electrodes. In this regard, the electrodes can be thought of as separate "charge-transfer catalysts".
Radiant or light energy is another form of energy that may be added to the reaction medium that also may have negative side effects but which may be different from (or the same as) those side effects from thermal energy. Addition of radiant energy to a system produces electronically excited molecules that are capable of undergoing chemical reactions.
A molecule in which all the electrons are in stable orbitals is said to be in the ground electronic state. These orbitals may be either bonding or non-bonding. If a photon of the proper energy collides with the molecule the photon may be absorbed and one of the electrons may be promoted to an unoccupied orbital of higher energy. Electronic excitation results in spatial redistribution of the valence electrons with concomitant changes in internuclear configurations. Since chemical reactions are controlled to a great extent by these factors, an electronically excited molecule undergoes a chemical reaction that may be distinctly different from those of its ground-state counterpart.
The energy of a photon is defined in terms of its frequency or wavelength,E=hv=hc/λwhere E is energy; h is Plank's constant, 6.6×10−34 J sec; v is the frequency of the radiation, sec−1; c is the speed of light; and λ is the wavelength of the radiation. When a photon is absorbed, all of its energy is typically imparted to the absorbing species. The primary act following absorption depends on the wavelength of the incident light. Photochemistry studies photons whose energies lie in the ultraviolet region (e.g., 100 Å-4000 Å) and in the visible region (e.g., 4000 Å-7000 Å) of the electromagnetic spectrum. Such photons are primarily a cause of electronically excited molecules.
Since the molecules are imbued with electronic energy upon absorption of light, reactions occur from different potential-energy surfaces from those encountered in thermally excited systems. However, there are several drawbacks of using the known techniques of photochemistry, that being, utilizing a broad band of frequencies thereby causing unwanted side reactions, undue experimentation, and poor quantum yield. Some good examples of photochemistry are shown in the following patents.
In particular, U.S. Pat. No. 5,174,877 issued to Cooper, et al. al., (1992) discloses an apparatus for the photocatalytic treatment of liquids. In particular, it is disclosed that ultraviolet light irradiates the surface of a prepared slurry to activate the photocatalytic properties of the particles contained in the slurry. The transparency of the slurry affects, for example, absorption of radiation. Moreover, discussions of different frequencies suitable for achieving desirable photocatalytic activity are disclosed.
Further, U.S. Pat. No. 4,755,269 issued to Brumer, et al. al., (1998) discloses a photodisassociation process for disassociating various molecules in a known energy level. In particular, it is disclosed that different disassociation pathways are possible and the different pathways can be followed due to selecting different frequencies of certain electromagnetic radiation. It is further disclosed that the amplitude of electromagnetic radiation applied corresponds to amounts of product produced.
Selective excitation of different species is shown in the following three (3) patents. Specifically, U.S. Pat. No. 4,012,301 to Rich, et al. al., (1977) discloses vapor phase chemical reactions that are selectively excited by using vibrational modes corresponding to the continuously flowing reactant species. Particularly, a continuous wave laser emits radiation that is absorbed by the vibrational mode of the reactant species.
U.S. Pat. No. 5,215,634 issued to Wan, et al., (1993) discloses a process of selectively converting methane to a desired oxygenate. In particular, methane is irradiated in the presence of a catalyst with pulsed microwave radiation to convert reactants to desirable products. The physical catalyst disclosed comprises nickel and the microwave radiation is applied in the range of about 1.5 to 3.0 GHz.
U.S. Pat. No. 5,015,349 issued to Suib, et al. al., (1991) discloses a method for cracking a hydrocarbon to create cracked reaction products. It is disclosed that a stream of hydrocarbon is exposed to a microwave energy which creates a low power density microwave discharge plasma, wherein the microwave energy is adjusted to achieve desired results. A particular frequency desired of microwave energy is disclosed as being 2.45 GHz.
Photoelectrochemistry has focussed on three main areas. In the first, light is shone on a metal electrode, but metals absorb broadband light very poorly and so this method is not greatly effective. The second area of photoelectric chemistry involves the passage of electrons in a solution by absorption of light by photoactive species resulting in electron generation. Again, these techniques use broadband methods and have drawbacks. The third area of photoelectricalchemistry considered by many to be the most promising involves the absorption of light by semiconductors in cell reaction systems, elevating electrons from valence bands to conduction bands. The semiconductors in electrodes function as photo-induced charge transfer catalysts.
Physical catalysts are well known in the art. Specifically, a physical catalyst is a substance which alters the reaction rate of a chemical reaction without appearing in the end product. It is known that some reactions can be speeded up or controlled by the presence of substances which themselves appear to remain unchanged after the reaction has ended. By increasing the velocity of a desired reaction relative to unwanted reactions, the formation of a desired product can be maximized compared with unwanted by-products. Often only a trace of physical catalyst is necessary to accelerate the reaction. Also, it has been observed that some substances, which if added in trace amounts, can slow down the rate of a reaction. This looks like the reverse of catalysis, and, in fact, substances which slow down a reaction rate have been called negative catalysts or poisons. Known physical catalysts go through a cycle in which they are used and regenerated so that they can be used again and again. A physical catalyst operates by providing another path for the reaction which can have a higher reaction rate or slower rate than available in the absence of the physical catalyst. At the end of the reaction, because the physical catalyst can be recovered, it appears the physical catalyst is not involved in the reaction. But, the physical catalyst must somehow take part in the reaction, or else the rate of the reaction would not change. The catalytic act has historically been represented by five essential steps originally postulated by Ostwald around the late 1800's:
1. Diffusion to the catalytic site (reactant);
2. Bond formation at the catalytic site (reactant);
3. Reaction of the catalyst-reactant complex;                4. Bond rupture at the catalytic site (product); and
5. Diffusion away from the catalytic site (product).
The exact mechanisms of catalytic actions are unknown in the art but it is known that physical catalysts can speed up a reaction that otherwise would take place too slowly to be practical.
There are a number of problems involved with known industrial catalysts: firstly, physical catalysts can not only lose their efficiency but also their selectivity, which can occur due to, for example, overheating or contamination of the catalyst; secondly, many physical catalysts include costly metals such as platinum or silver and have only a limited life span, some are difficult to rejuvenate, and the precious metals may not be easily reclaimed. There are numerous physical limitations associated with physical catalysts which render them less than ideal participants in many reactions.
Accordingly, what is needed is an understanding of the catalytic process so that biological processing, chemical processing, industrial processing, etc., can be engineered by more precisely controlling the multitude of reaction processes that currently exist, as well as developing completely new reaction pathways and/or reaction products. Examples of such understandings include methods to catalyze reactions without the drawbacks of: (1) known physical catalysts; and (2) utilizing energy with much greater specificity than the prior art teachings which utilize less than ideal thermal and electromagnetic radiation methods and which result in numerous inefficiencies.
Accordingly, what is also needed are techniques for electrochemistry which improve the functioning of electrodes as charge-transfer catalysts. Further, improvements are required in the transport of ions and charges through electrolyte solutions. Passage of electrons through metals and semiconductors is not rate-limiting, rather it is the passage of ions and charged species through solutions that is slow.
Definitions
For the purposes of this invention, the terms and expressions below, appearing in the Specification and Claims, are intended to have the following meanings:
"Activated complex", as used herein, means the assembly of atom(s) (charged or neutral) which corresponds to the maximum in the reaction profile describing the transformation of reactant(s) into reaction product(s). Either the reactant or reaction product in this definition could be an intermediate in an overall transformation involving more than one step.
"Alkaline battery" or "alkaline cell", as used herein, means a cell which utilizes an aqueous solution of alkaline potassium hydroxide as the electrolyte. One electrode comprises zinc and the other electrode comprises manganese dioxide. In batteries, the zinc is typically present as a high surface area powder and the electrolyte is typically gelled. The typical half-reactions are:Zn+2OH−=Zn(OH)2+2e−; and2MnO2+H2O+2e−=Mn3O2+2OH−.
"Alkaline fuel cell", as used herein, means a fuel cell which utilizes an aqueous solution of alkaline potassium hydroxide soaked in a matrix as the electrolyte. Operating temperatures are about 150-200° C.
"Anode", as used herein, means the electrode where oxidation occurs in an electrochemical cell. It is the positive electrode in an electrolytic cell, while it is the negative electrode in a galvanic cell.
"Anode effect", as used herein, means a particular condition in an electrolytic cell that produces a quick increase in cell voltage and a corresponding decrease in current flow. This effect is usually caused by the temporary formation of an insulating layer on the anode surface. It occurs almost exclusively in molten salt electrolysis (e.g., aluminum production).
"Anodic protection" or "corrosion protection", as used herein, means a process for corrosion protection of a metal or an alloy achieved by causing an anodic current of appropriate magnitude to form a passive film on the material used as the anode in an electrolytic cell. Anodic protection is utilized for metals such as stainless steel and titanium.
"Anodizing", as used herein means, the process of producing an oxide film or coating on metals or alloys by the process of electrolysis. The metal which is coated functions as an anode in an electrolytic cell and the surface of the anode (i.e., metal) is electrochemically oxidized. Anodization improves certain properties including, for example, corrosion resistance, abrasion resistance, and hardness.
"Applied spectral energy conditioning pattern", as used herein, means the totality of: (a) all spectral energy conditioning patterns that are externally applied to a conditionable participant; and/or (b) spectral conditioning environmental reaction conditions that are used to condition one or more conditionable participants to form a conditioned participant in a conditioning reaction system.
"Applied spectral energy pattern", as used herein, means the totality of: (a) all spectral energy patterns that are externally applied; and/or (b) spectral environmental reaction conditions input into a cell reaction system.
"Backing layers", as used herein, means a portion of some fuel cells which is/are located adjacent to each electrode that provide for partial support of such electrode(s) and for diffusion (e.g., interconnected porosity may be provided) of, for example, reactants toward an electrode and/or reaction products away from an electrode.
"Battery", as used herein, means a device which stores an electrical energy using electrochemical cells. Chemical reactions occur spontaneously at the electrodes when the electrodes are connected by an external circuit producing an electric current. Batteries are typically comprised of several, internally connected, electrochemical cells (i.e., batteries often contain several cells). However, the term "battery" and "cell" are often interchangeably used.
"Bioelectrochemistry", as used herein, means the electrochemical reactions that occur in biological systems and/or biological compounds.
"Bi-polar electrode", as used herein, means an electrode that is shared by two-series coupled electrochemical cells such that one side of the electrode acts as an anode in a first cell and the other side of the electrode acts as a cathode in an adjacent cell. These electrodes are often used in storage batteries and fuel cell stacks that connect many cells internally.
"Brine electrolysis", as used herein, means electrolysis of an aqueous solution of sodium chloride, also known as "brine", which results in the production of chlorine gas at the anode and hydrogen gas at the cathode. The overall cell reaction is:2NaCl+2H2O=Cl2+H2+2NaOH.
"Capacitance", as used herein, means the ability of a capacitor to store electrical charge. The unit of capacitance is the Farad.
"Capacitive current" or "current density", as used herein, means the current, or current density flowing through an electrochemical cell that is charging/discharging an electrical double-layer capacitance. This current does not involve chemical reactions, rather, the current results in accumulation (or removal) of electrical charges on the electrode and in the electrolyte solution near the electrode.
"Capacitor" or "capacitor cells", as used herein, means an electrical device which stores electricity or electrical energy. It includes three essential parts, two electrodes, (e.g., metal plates) which are physically separated from each other and are, typically, substantially parallel to each; and located therebetween is a third part known as a dielectric. The electrodes are charged with a substantially equal amount of positive and negative electrical charges, respectively. Capacitors result in a physical storage of electricity rather than a chemical storage of electricity.
"Catalytic spectral conditioning pattern", as here herein, means at least a portion of a spectral conditioning pattern of a physical catalyst which when applied to a conditionable participant can condition the conditionable participant to catalyze and/or assist in catalyzing the cell reaction system by the following:
completely replacing a physical chemical catalyst;
acting in unison with a physical chemical catalyst to increase the rate of reaction;
reducing the rate of reaction by acting as a negative catalyst; or
altering the reaction pathway for formation of a specific reaction product.
"Catalytic spectral energy conditioning pattern", as used herein, means at least a portion of a spectral energy conditioning pattern which when applied to a conditionable participant in the form of a beam or field can condition the conditionable participant to form a conditioned participant having a spectral energy pattern corresponding to at least a portion of a spectral pattern of a physical catalyst which catalyzes and/or assists in catalyzing the cell reaction system when the conditioned participant is placed into, or becomes involved with, the cell reaction system.
"Catalytic spectral energy pattern", as used herein, means at least a portion of a spectral energy pattern of a physical catalyst which when applied to a cell reaction system in the form of a beam or field can catalyze a particular reaction in the cell reaction system.
"Catalytic spectral pattern", as used herein, means at least a portion of a spectral pattern of a physical catalyst which when applied to a cell reaction system can catalyze a particular reaction by the following:
a) completely replacing a physical chemical catalyst;
b) acting in unison with a physical chemical catalyst to increase the rate of reaction;
c) reducing the rate of reaction by acting as a negative catalyst; or
d) altering the reaction pathway for formation of a specific reaction product.
"Cell", as used herein, means a fundamental unit comprising at least two material(s) functioning as electrodes and at least one substance or material (e.g., at least a portion of which is an electrolyte or a dielectric) located between the electrodes. These fundamental units can be organic, biologic and/or inorganic.
"Cell reaction system", as used herein, means all the constituents in a cell (e.g., galvanic cell, battery, fuel cell, electrochemical cell, electrolytic cell, photoelectrochemical cell, photogalvanic cell, photoelectrolytic cell, capacitor, electrochemical processes, etc.), including, but not limited to, reactants, intermediates, transients, activated complexes, physical catalysts, poisons, promoters, solvents, physical catalyst support materials, spectral catalysts, spectral energy catalysts, reaction products, environmental reaction conditions, spectral environmental reaction conditions, applied spectral energy pattern, reaction vessels, containers, electrolytes, electrodes, backing layers, flow fields, housings, etc., that are involved in any reaction pathway.
"Concentration", as used herein, means a measure of the amount of a dissolved material (i.e., solute) in a solution.
"Concentration cell", as used herein, means a galvanic cell in which the chemical energy converted into electrical energy comes from a concentration difference of a species at the two electrodes in the cell.
"Condition" or "conditioning", as used herein, means the application or exposure of a conditioning energy or combination of conditioning energies to at least one conditionable participant prior to the conditionable participant becoming involved (e.g., being placed into a cell reaction system and/or prior to being activated) in the cell reaction system.
"Conditionable participant", as used herein, means reactant, physical catalyst, solvent, physical catalyst support material, reaction vessel, conditioning reaction vessel, promoter and/or poison comprised of molecules, macromolecules, ions and/or atoms (or components thereof) in any form of matter (e.g., solid, liquid, gas, plasma) that can be conditioned by an applied spectral energy conditioning pattern.
"Conditioned participant", as used herein, means reactant, physical catalyst, solvent, physical catalyst support material, reaction vessel, conditioning reaction vessel, physical promoter and/or poison comprised of molecules, ions and/or atoms (or components thereof) in any form of matter (e.g., solid, liquid, gas, plasma) that has been conditioned by an applied spectral energy conditioning pattern.
"Conditioning energy", as used herein means at least one of the following spectral energy conditioning providers: spectral energy conditioning catalyst; spectral conditioning catalyst; spectral energy conditioning pattern; spectral conditioning pattern; catalytic spectral energy conditioning pattern; catalytic spectral conditioning pattern; applied spectral energy conditioning pattern and spectral conditioning environmental reaction conditions.
"Conditioning environmental reaction condition", as used herein, means and includes traditional reaction variables such as temperature, pressure, surface area of catalysts, physical catalyst size and shape, concentrations, electromagnetic radiation, electric fields, magnetic fields, mechanical forces, acoustic fields, reaction vessel size, shape and composition and combinations thereof, etc., which may be present and are capable of influencing, positively or negatively, the conditioning of at least one conditionable participant.
"Conditioning reaction system", as used herein, means the combination of reactants, physical catalysts, poisons, promoters, solvents, physical catalyst support materials, conditioning reaction vessel, reaction vessel, spectral conditioning catalysts, spectral energy conditioning catalysts, conditioned participants, environmental conditioning reaction conditions, spectral environmental conditioning reaction conditions, applied spectral energy conditioning pattern, etc., that are involved in any reaction pathway to form a conditioned participant.
"Conditioning reaction vessel", as used herein, means the physical vessel(s) or containment system(s) which contains or houses all components of the conditioning reaction system, including any physical structure or media which are contained within the vessel or system.
"Conditioning targeting", as used herein, means the application of conditioning energy to a conditionable participant to condition the conditionable participant prior to the conditionable participant being involved, and/or activated, in a holoreaction system, said conditioning energy being provided by at least one of the following spectral energy conditioning providers: spectral energy conditioning catalyst; spectral conditioning catalyst; spectral energy conditioning pattern; spectral conditioning pattern; catalytic spectral energy conditioning pattern; catalytic spectral conditioning pattern; applied spectral energy conditioning pattern; and spectral environmental conditioning reaction conditions, to achieve (1) direct resonance; and/or (2) harmonic resonance; and/or (3) non-harmonic heterodyne-resonance with at least a portion of at least one of the following conditionable participants: reactants; physical catalysts; promoters; poisons; solvents; physical catalyst support materials; reaction vessels; conditioning reaction vessels; conditioning reaction vessels and/or mixtures or components thereof (in any form of matter), said spectral energy conditioning provider providing conditioning energy to condition at least one conditionable participant by interacting with at least one frequency thereof, to form at least one conditioned participant which assists in producing at least one desired reaction product and/or at least one desired reaction product at a desired reaction rate, when the conditioned participant becomes involved with, and/or activated in, a cell reaction system.
"Corrosion", as used herein, means chemical processes, as well as electrochemical processes, that destroy structural materials. Typically, it refers to corrosions of metals, but other materials (e.g., plastics or semiconductors) also exhibit corrosion. Metallic corrosion is most always an electrochemical process when the metal is immersed in a solution. However, certain atmospheric conditions which result in, for example, thin-films of moisture often result in similar electrochemical processes occurring on at least a portion of a metal. Metal in the corrosive solution functions as a short-circuited galvanic cell. In particular, a first portion of a surface of the metal acts as an anode and another portion acts as a cathode. Oxidation occurs at the anodic areas, whereas at the cathodic areas dissolved oxygen is reduced. Accordingly, the spontaneous complimentary redox reaction of rusting causes electrical current to be flowing into/from two different parts in a metal.
"Current", as used herein, means the movement of electrical charges in a conductor (e.g., electrons moving in an electronic conductor and ions moving in an ionic conductor). Electrochemistry uses almost exclusively direct current. Accordingly, unless mentioned in context of the disclosure herein, the use of the term "current" is typically in connection with direct currents. The typical unit of a current is an ampere.
"Current collector", as used herein, means a plate or device which can conduct electrons produced by, for example, an oxidation reaction at an anode. These devices are typically plates that also may incorporate a flow field and are thus made from materials that are typically relatively impervious to reactants and/or reaction products under the process conditions of the cell reaction system.
"Cycle life", as used herein, means the number of times a rechargeable battery can be cycled (i.e., charged and discharged) before the battery or cell loses its ability to accept charge.
"Dielectric", as used herein, means a material present between electrodes in a capacitor.
"Dielectric constant", as used herein, means the relative permittivity of a material compared to the permittivity of a vacuum. Different materials have different dielectric constants which are determined by the following equation:Eactual=ErEo,where Eactual is the actual permittivity; Er is the dielectric constant and Eo is the permittivity of a vacuum.
"Diffusion layer", as used herein, means a thin-liquid boundary layer at the surface of an electrode that is immobile. This immobile layer is part of a model which is often referred to as the "Nernstian Hypothesis". In this approach, the electrolyte solution is divided into three distinct parts, the bulk solution and two diffusion layers located at or near the surfaces of the electrodes. The bulk solution is assumed to be homogenous. Thus, mass transport occurs primarily through convection. However, in the diffusion layers, mass transport occurs primarily through diffusion. Charge transport occurs by an electric migration approach everywhere within a cell. However, the thickness of the diffusion layer typically varies between about 0.01 cm to about 0.0001 cm. Diffusion layers can affect the functioning of cells.
"Direct methanol fuel cell", as used herein, means a fuel cell which utilizes a polymer membrane as the electrolyte and an anode catalyst which itself manufacturers hydrogen as fuel, said hydrogen fuel being produced for the fuel cell from a liquid methanol precursor (e.g., thus eliminating the need for a fuel reformer). These fuel cells typically operate at temperatures between 50-100° C.
"Direct resonance conditioning targeting", as used herein, means the application of conditioning energy to a conditionable participant to condition the conditionable participant prior to the conditionable participant being involved, and/or activated, in a cell reaction system, said conditioning energy being provided by at least one of the following spectral energy conditioning providers: spectral energy conditioning catalyst; spectral conditioning catalyst; spectral energy conditioning pattern; spectral conditioning pattern; catalytic spectral energy conditioning pattern; catalytic spectral conditioning pattern; applied spectral energy conditioning pattern and spectral conditioning environmental reaction conditions, to achieve direct resonance with at least a portion of at least one conditionable participant (e.g.; reactants; physical catalysts; promoters; poisons; solvents; physical catalyst support materials; reaction vessels; conditioning reaction vessels and/or mixtures or components thereof in any form of matter), said spectral energy conditioning providers providing conditioning energy to condition at least one conditionable participant(s) by interacting with at least one frequency thereof to form at least one conditioned participant, which assists in producing at least one desired reaction product and/or at least one desired reaction product at a desired reaction rate, when the conditioned participant becomes involved with, and/or activated in, a cell reaction system.
"Direct resonance targeting", as used herein, means the application of energy to a cell reaction system by at least one of the following spectral energy providers: spectral energy catalyst; spectral catalyst; spectral energy pattern; spectral pattern; catalytic spectral energy pattern; catalytic spectral pattern; applied spectral energy pattern and spectral environmental reaction conditions, to achieve direct resonance with at least one of the following forms of matter: reactants; transients; intermediates; activated complexes; physical catalysts; reaction products; promoters; poisons; solvents; physical catalyst support materials; reaction vessels; and/or mixtures or components thereof, said spectral energy providers providing energy to at least one of said forms of matter by interacting with at least one frequency thereof, to produce at least one desired reaction product and/or at least one desired reaction product at a desired reaction rate.
"Dry cell", as used herein, means a non-rechargeable battery wherein the electrolyte is immobilized by a gelling agent. The whole cell is typically sealed.
"Electrical double layer", as used herein, means the structure of charge accumulation and charge separation that occurs at the interface between an electrode and an electrolyte when an electrode is, for example, immersed in an electrolyte solution.
"Electrical potential", as used herein, means the difference in potential between two points in a circuit.
"Electrical power", as used herein, means the rate at which an electrical source can supply electrical energy. Electrical power is often expressed in the units of watts. Watts relate to the rate at which energy can be delivered.
"Electroacoustics or "electroacoustic effect", as used herein, means electrokinetic effects arising when sound waves cause certain oscillations of one or more parts in a cell.
"Electroanalytical chemistry", as used herein, means the application of electrochemical cells and electrochemical techniques for electrochemical analysis. The material to be analyzed is dissolved in the electrolyte of a cell.
"Electrochemical cell", as used herein, means a device that converts chemical energy into electrical energy. It includes two electrodes which are separated by an electrolyte. The electrodes may comprise any electrically conducting material (e.g., solid or liquid metals, semiconductors, etc.) which can communicate with each other through an electrolyte. These cells experience separate oxidation and reduction reactions at each electrode.
"Electrocrystallization", as used herein, means an electroplating technique that results in a crystalline metal deposit on one electrode (e.g., typically the cathode in an electrolytic cell).
"Electrode", as used herein, means one of the two electronically conducting parts in an electrochemical cell, galvanic cell, electrolytic cell and/or capacitor, through which electrons are transported and/or exchanged with chemical reactants in a cell.
"Electroforming", as used herein, means a process to produce metallic objects by an electroplating technique. The metal is deposited onto a forming object (e.g., mandrel) of suitable shape and to a desired thickness, followed by the removal of the forming object to result in a freestanding metal object.
"Electrokinetic effects" or "electrokinetics", as used herein, means a process that arises due to a charge separation caused by the relative motion of a solid and liquid phase. A portion of the so-called "Gouy-Chapman diffuse layer" is sheared as the two phases move relative to each other, resulting in a charge separation.
"Electrolysis", as used herein, means a process that decomposes a chemical compound into its constituent elements and/or a process which produces a new compound by the action of an electrical current. Redox reactions typically occur at the electrode (e.g., water is decomposed to hydrogen and oxygen by this process).
"Electrolyte", as used herein, means a substance located between at least a portion of an anode and a cathode and which is composed of at least some positive and negative ions and which is capable of transporting at least one ionic species therethrough.
"Electrolytic capacitor", as used herein, means a storage device similar to other types of electrical capacitors, however, one of the conducting phases in this material is a metallic plate, and the other conducting phase is an electrolyte solution. The dielectric is typically a thin oxide film on the surface of the metal (e.g., aluminum or tantalum) that comprises one conducting phase of the capacitor.
"Electrolytic cell", as used herein, means an electrochemical cell that converts electrical energy into chemical energy. The chemical reactions typically do not occur spontaneously at the electrodes when the electrodes are connected through an external circuit. The chemical reaction is typically forced by applying an external electric current to the electrodes. This cell is used to store electrical energy in chemical form such as in, for example, a secondary or rechargeable battery. The process of water being decomposed into hydrogen gas and oxygen is termed electrolysis and such electrolysis is performed in an electrolytic cell.
"Electrolytic pickling", as used herein, means a process for removing oxide scales from metal surfaces in preparation for electroplating. The metal for which oxide scales are to be removed from is the cathode in an electrolytic cell and the electrolyte contains a strong acidic solution that dissolves oxide scales.
"Electrometallurgy", as used herein, means a branch of metallurgy which utilizes electrochemical processes known as electrowinning.
"Electromigration", as used herein, means the movement of ions under the influence of electrical potential difference.
"Electrophoresis", as used herein, means the movement of small-suspended particles or large molecules in a liquid, such movement being driven by an electrical potential difference.
"Electroplating", as used herein, means a process that produces a thin, metallic coating on the surface of another material (e.g., a metal or another electrically conducting material such as graphite). The substrate to be coated is situated to be the cathode in an electrolytic cell, where the cations of the electrolyte becomes the positive ions of the metal to be coated on the surface of the cathode. When a current is applied, the electrode reaction occurring on the cathode is a reduction reaction causing the metal ions to become metal on the surface of the cathode.
"Electrorefining", as used herein, means a process that produces a purified metal from a less pure metal. The metal to be purified is situated to be the anode in an electrolytic cell and the anode is dissolved by the application of a current into a usually acidic aqueous electrolyte or a molten salt solution. At the same time, the pure metal is electroplated on the cathode. Examples of electrorefining include copper that is electrorefined in aqueous solutions; and aluminum that is electrorefined using a molten salt electrolyte.
"Electrowinning", as used herein, means an electrochemical process that produces metals from their ores. In particular, metal oxides typically occur in nature and electrochemical reduction is one of the most economic methods for producing metals from these ores. In particular, the ore is dissolved in an acidic aqueous solution or molten salt and the resulting electrolyte solution is electrolyzed. The metal is electroplated on the cathode (e.g., either in a solid or liquid form) while oxygen is involved in the reaction at the anode. Copper, zinc, aluminum, magnesium and sodium are manufactured by this technique.
"Energy density", as used herein, means the amount of electrical energy stored per unit weight or volume in a cell or battery.
"Energy efficiency", as used herein, in reference to a rechargeable battery is expressed as a percentage of charge that is recoverable during discharging.
"Environmental reaction condition", as used herein, means and includes traditional reaction variables such as temperature, pressure, surface area of catalysts, physical catalyst size and shape, concentrations, electromagnetic radiation, electric fields, magnetic fields, mechanical forces, acoustic fields, reaction vessel size, shape and composition and combinations thereof, etc., which may be present and are capable of influencing, positively or negatively, reaction pathways in a cell reaction system.
"Faraday's laws", as used herein, means: (1) in any electrolytic process the amount of chemical change produced is proportional to the total amount of electrical charge passed through the cell; and (2) the mass of the chemicals changed is proportional to the equivalent weight of the chemicals involved. The proportionality constant is referred to as the "Faraday Number".
"Flow fields", as used herein, are present in some cells (e.g., fuel cells) and are typically, located adjacent to backing plates. Flow field plates or devices often serve a dual function as current collectors. The flow fields are typically plates made of lightweight but strong and gas-impermeable electron-conducting materials. Typical materials include graphites or metals. These plates are typically located adjacent to backing layers and include at least one channel which is utilized to carry, for example, reactant gases to an active area of a membrane/electrode assembly. These plates also conduct electrons produced by oxidation of the anode.
"Frequency", as used herein, means the number of times which a physical event (e.g., wave, field and/or motion) varies from the equilibrium value through a complete cycle in a unit of time (e.g., one second; and one cycle/sec=1 Hz). The variation from equilibrium can be positive and/or negative, and can be, for example, symmetrical, asymmetrical and/or proportional with regard to the equilibrium value.
"Fuel cell", as used herein, means an electrochemical device that continuously converts the chemical energy of at least one externally supplied fuel and at least one oxidant directly to electrical energy.
"Fuel cell reaction system", as used herein, means all constituents in a fuel cell including, but not limited to, reactants, intermediates, transients, activated complexes, physical catalysts, poisons, promoters, solvents, physical catalyst support materials, spectral catalysts, spectral energy catalysts, reaction products, environmental reaction conditions, spectral environmental reaction conditions, applied spectral energy pattern, electrolytes, electrodes, backing layers, flow fields, etc., that are involved in any reaction pathway.
"Galvanic cell", as used herein, means an electrochemical cell that converts chemical energy into electrical energy. Chemical reactions, in this cell occur spontaneously at the electrodes when the electrodes are connected by an external circuit, producing an electrical current. Examples of these cells include fuel cells and batteries.
"Galvanizing", as used herein, means a process for coating iron or steel with a thin layer of zinc for corrosion protection. Galvanizing is performed electrochemically by an electroplating process or by a hot-dip galvanizing process which consists of immersing the metal into a molten zinc.
"Gas electrode", as used herein, means any electrode in gaseous phase.
"Harmonic conditioning targeting", as used herein, means the application of conditioning energy to a conditionable participant to condition the conditionable participant prior to the conditionable participant becoming involved, and/or activated, in a cell reaction system, said conditioning energy being provided by at least one of the following spectral energy conditioning providers: spectral energy conditioning catalyst; spectral conditioning catalyst; spectral energy conditioning pattern; spectral conditioning pattern; catalytic spectral energy conditioning pattern; catalytic spectral conditioning pattern; applied spectral energy conditioning pattern and spectral conditioning environmental reaction conditions, to achieve harmonic resonance with at least a portion of at least one conditionable participant (e.g.; reactants; physical catalysts; promoters, poisons; solvents; physical catalyst support materials; reaction vessels; conditioning reaction vessels; and/or mixtures or components thereof in any form of matter), said spectral energy conditioning provider providing conditioning energy to condition at least one conditionable participant(s) by interacting with at least one frequency thereof, to form at least one conditioned participant which assists in producing at least one desired reaction product and/or at least one desired reaction product at a desired reaction rate when the conditioned participant becomes involved with, and/or activated in, a cell reaction system.
"Harmonic targeting", as used herein, means the application of energy to a cell reaction system by at least one of the following spectral energy providers: spectral energy catalyst; spectral catalyst; spectral energy pattern; spectral pattern; catalytic spectral energy pattern; catalytic spectral pattern; applied spectral energy pattern and spectral environmental reaction conditions, to achieve harmonic resonance with at least one of the following forms of matter: reactants; transients; intermediates; activated complexes; physical catalysts; reaction products; promoters, poisons; solvents; physical catalyst support materials; reaction vessels; and/or mixtures or components thereof, said spectral energy providers providing energy to at least one of said forms of matter by interacting with at least one frequency thereof, to produce at least one desired reaction product and/or at least one desired reaction product at a desired reaction rate.
"Holoreaction system", as used herein, means all components of the cell reaction system and the conditioning reaction system.
"Hydrolysis", as used herein, means a chemical reaction in which water reacts with another substance and causes decomposition of other products, often including the reaction of water with a salt to create an acid or a base.
"Indirect electrolysis", as used herein, means the production of chemicals in an electrolytic cell through intermediate electrolysis products. In particular, an intermediate oxidizing/reducing agent is produced at an electrode surface and the produced material can react with another material in the bulk solution.
"Intermediate", as used herein, means a molecule, ion and/or atom which is present between a reactant and a reaction product in a reaction pathway or reaction profile. It corresponds to a minimum in the reaction profile of the reaction between reactant and reaction product. A reaction which involves an intermediate is typically a stepwise reaction.
"Ion-exchange membrane", as used herein, means a sheet formed from an ion exchange resin. These membranes typically allow only either positive ions (i.e., cation-exchange membranes) or negative ions (i.e., anion-exchange membranes) to be transmitted.
"Ion-exchange resin", as used herein, means a polymeric resin that contains electrically charged fragments (i.e., fixed ions) permanently attached to the polymer backbone; and wherein electrical neutrality is achieved by attached mobile "counter-ions" in the solution phase into which the resin is immersed.
"Laclanch-type cell", as used herein, means a cell which utilizes a zinc anode and a manganese dioxide cathode with ammonium chloride or zinc chloride solution as an electrolyte. The electrolyte may be immobilized permitting the cell to be a dry cell. The overall cell reaction is:Zn+2MnO2+2H2O+ZnCl2=2MnOOH+2Zn(OH)Cl.
"Lead-acid cell" or "Pb/acid battery", as used herein, means a cell or battery which utilizes a rechargeable acidic electrolyte and electrodes of lead and lead-oxide. The cathode is typically lead-oxide, the anode is typically lead and the electrolyte is typically sulfuric acid. The typical half-reactions are:Pb+SO42−=PbSO42−(sol)+2e−; andPbO2+4H++2e−+SO42−(sol)=PbSO42−(sol).
"Lithium cell" or "Lithium battery", as used herein, means a cell which utilizes lithium as an anode and various materials as cathodes including CF, MnO2, FeS2 and I2. Various non-aqueous electrolytes comprised of polar-organic liquids (e.g., dimethyl ether, propylene carbonate, etc.) containing a dissolved lithium salt are used. Additionally, various polymer-based electrolytes such as polyethylene oxide/salt complexes have also been used. Typical half-reactions include the following:Zn=Zn2++2e−Cd=Cd2++2e−Li=Li++e−.Examples of overall cell reactions include:Li(CF)n=LiF+C;Li+MnO2=LiMnO2;Li+FeS2=Li2S+Fe;andLi+½I2=LiI.
"Lithium ion battery" or "Lithium ion cell", as used herein, means a rechargeable cell which functions in a somewhat similar manner to the lithium cell. These batteries have very good power to weight ratios.
"Magnetoelectrochemistry", as used herein, means electrochemical phenomena occurring under the influence of magnetic field(s).
"Mass transport", as used herein means the movement or transportation of mass (e.g., chemical compounds, ions, etc.) from one part of a system to another. This phenomena is typically associated with diffusion and convection, but can also occur through electromigration.
"Membrane/Electrode assembly" or "MEA", as used herein, means the combination of the anode/membrane/cathode in a fuel cell. The assembly also often includes a catalyst on, in and/or around at least a portion of one or both of the electrodes.
"Molten carbonate fuel cell" or "MCFC", as used herein, means fuel cells which use a liquid solution of lithium, sodium and/or potassium carbonates, soaked in a matrix for an electrolyte. These fuel cells typically operate at temperatures of about 650° C. or higher. These higher temperatures are required in order to achieve sufficient conductivity of ions through the electrolyte. Due to these operating temperatures, metal catalysts are typically not required for electrochemical oxidation and reduction reactions. These cells operate on various fuels including, but not limited to, hydrogen, carbon monoxide, natural gas, propane, landfill gas, marine diesel and/or simulated coal gasification products.
"Nernst equation", as used herein, means an equation which defines the equilibrium potential of an electrode. The potential is the sum of the standard electrode potential and a correction term for the deviation from unit concentrations of reactant and product from the electrode reaction.
"NiCd battery" or "NiCd cell", as used herein, means a cell which utilizes Ni(OH)2 as the cathode, a Cd anode and an aqueous potassium hydroxide (KOH) electrolyte. The overall cell reaction is:2NiOOH+2H2O+Cd=2Ni(OH)2+Cd(OH)2.These cells have high cycle life (i.e., into the thousands) and long shelf lives without significant self-discharge. However, these cells have somewhat lower power densities.
"NIMH battery" or Nickel Metal Hydride Cell", as used herein means, an anode comprising a metal hydride electrode that serves as a solid source of hydrogen. Classical examples of anodes used in these cells include alloys of V, Ti, Zr, Ni, Cr, Co and Fe. The cathode comprises nickel and the electrolyte comprises aqueous KOH.
"Non-harmonic heterodyne conditioning targeting", as used herein, means the application of conditioning energy to a conditionable participant to condition the conditionable participant prior to the conditionable participant being involved, and/or activated, in a cell reaction system, said conditioning energy being provided by at least one of the following spectral energy conditioning providers: spectral energy conditioning catalyst; spectral conditioning catalyst; spectral energy conditioning pattern; spectral conditioning pattern; catalytic spectral energy conditioning pattern; catalytic spectral conditioning pattern; applied spectral energy conditioning pattern and spectral conditioning environmental reaction conditions, to achieve non-harmonic heterodyne resonance with at least a portion of at least one conditionable participant (e.g.; reactants; physical catalysts; promoters; poisons; solvents; physical catalyst support materials; reaction vessels; conditioning reaction vessels and/or mixtures or components thereof in any form of matter), said spectral energy conditioning provider providing conditioning energy to condition at least one conditionable participant by interacting with at least one frequency thereof, to form at least one conditioned participant which assists in producing at least one desired reaction product and/or at least one desired reaction product at a desired reaction rate when the conditioned participant becomes involved with, and/or activated in, a cell reaction system.
"Non-harmonic heterodyne targeting", as used herein, means the application of energy to a cell reaction system by at least one of the following spectral energy providers: spectral energy catalyst; spectral catalyst; spectral energy pattern; spectral pattern; catalytic spectral energy pattern; catalytic spectral pattern; applied spectral energy pattern and spectral environmental reaction condition to achieve non-harmonic heterodyne resonance with at least one of the following forms of matter: reactants; transients; intermediates; activated complexes; physical catalysts; reaction products; promoters; poisons; solvents; physical catalyst support materials; reaction vessels; and/or mixtures or components thereof, said spectral energy provider providing energy to at least one of said forms of matter by interacting with at least one frequency thereof, to produce at least one desired reaction product and/or at least one desired reaction product at a desired reaction rate.
"Overpotential", as used herein, means a difference in the electrode potential of an electrode between its equilibrium potential and its operating potential when a current is flowing.
"Overvoltage", as used herein, means the difference between cell voltage with a current flowing and an open-circuit voltage.
"Participant", as used herein, means reactant, current, transient, intermediate, activated complex, physical catalyst, promoter, poison and/or reaction product comprised of molecules, macromolecules, ions and/or atoms (or components thereof).
"Phosphoric acid fuel cell" or "PAFC", as used herein, means the electrolyte utilized is liquid phosphoric acid soaked in a matrix. Operating temperatures are in the range of about 150-200° C. These types of fuel cells typically use a noble metal, such as platinum, as a catalyst.
"Photoelectrochemical cell" or "photogalvanic cell" or "solar cell", as used herein, means a galvanic cell wherein usable current and voltage are simultaneously produced upon absorption of light by at least one of the electrodes.
"Photoelectrochemistry", as used herein, means the interaction of light with electrochemical systems.
"Photoelectrolytic cell", as used herein, means an electrolytic cell wherein the production of chemicals is caused, or influenced, by the absorption of light by at least one of the electrodes. The process occurring in such a cell is termed photoelectrosynthesis.
"Photoelectrosynthesis", as used herein, means the production of chemicals in a photoelectrolytic cell, where the production is caused, or influenced, by the absorption of light by at least one of the electrodes.
"Plasma", as used herein means, an approximately electrically neutral (quasineutral) collection of electrically activated atoms or molecules, or ions (positive and/or negative) and electrons which may or may not contain a background neutral gas, and at least a portion of which is capable of responding to at least electric and/or magnetic fields.
"Polymer electrolyte membrane fuel cell" or "PEMFC", as used herein, means those fuel cells which utilize a polymer or proton exchange membrane which, typically, comprises a relatively thin polymer sheet. The polymer membrane is, typically, coated on both sides with a mixture of a catalyst and an electron conductor. The electrolyte is typically a solid organic polymer known as a sulfonated fluoroethylene or a poly-perflourosulfonic acid. Hydrogen is the fuel source typically used and is fed to the anode side of the cell where hydrogen atoms are created and reduced to hydrogen ions (i.e., protons) which are then conducted through the polymer electrolyte to the anode side of the cell, where they are combined with oxygen and electrons to form water.
"Power density", as used herein, means a parameter in a battery indicating the electrical power per unit weight or per unit volume.
"Primary cell" or "primary battery" or "non-rechargeable battery", as used herein, means a cell or battery in which the chemical reaction system providing the electrical current is not readily reversible by a chemical process. This cell provides current until substantially all of the chemicals inside it are utilized. The cell or battery is typically discarded after a single discharge. This cell or battery always operates as a galvanic cell in which the anode is the negative electrode and the cathode is the positive electrode.
"Protonic-ceramic fuel cell", as used herein, means a ceramic material is used as the electrolyte and the ceramic exhibits high protonic conductivity at elevated temperatures. These types of fuel cells operate at relatively high temperatures of at least about 700° C. The high operating high temperatures permit electrochemical oxidation of fossil fuels directly at, for example, the anode. Accordingly, hydrogen ions are formed at the electrode even when precursors to hydrogen are supplied, and such hydrogen ions are then absorbed directly into the electrolyte. Carbon dioxide is the primary reaction product of these fuel cells.
"Reactant", as used herein, means a starting material or starting component in a cell reaction system. A reactant can be any inorganic, organic and/or biologic atom, molecule, macromolecule, ion, compound, substance, and/or the like.
"Reaction coordinate", as used herein, means an intra- or inter-molecular/atom configurational variable whose change corresponds to the conversion of reactant into reaction product.
"Reaction pathway", as used herein, means those steps which lead to the formation of reaction product(s). A reaction pathway may include intermediates and/or transients and/or activated complexes. A reaction pathway may include some or all of a reaction profile.
"Reaction product", as used herein, means any product of a reaction involving a reactant. A reaction product may have a different chemical composition from a reactant or a substantially similar (or exactly the same) chemical composition but exhibit a different physical or crystalline structure and/or phase and/or properties. A reaction product may also be a current. "Reaction profile", as used herein means a plot of energy (e.g., molecular potential
energy, molar enthalpy, or free energy) against reaction coordinate for the conversion of reactant(s) into reaction product(s).
"Regenerative fuel cells", as used herein, means a closed-looped form of power generation. In particular, water is typically separated into hydrogen and oxygen by a solar-powered electrolyzing source. The hydrogen and oxygen are then fed into a fuel cell (e.g., a PEM fuel cell) to generate electricity, heat and water. The reaction product of water is then recirculated back to the solar powered electrolyzer and the process begins again in a closed-looped manner.
"Residual current" or "residual current density", as used herein, means a small faradic current density flowing through an electrode under conditions where zero faradic current is expected (e.g., within an electrical double-layer range). This type of current is typically caused by traces of impurities present in the electrolyte.
"Resultant energy conditioning pattern", as used herein, means the totality of energy interactions between the applied spectral energy conditioning pattern with at least one conditionable participant before said conditionable participant becomes involved, and/or activated, in a cell reaction system as a conditioned participant.
"Resultant energy pattern", as used herein, means the totality of energy interactions between the applied spectral energy pattern with all participants and/or components in the cell reaction system.
"Secondary cell" or "secondary battery" or "rechargeable battery", as used herein, means a cell or battery in which the chemical reaction system providing electrical current is readily reversible chemically. Specifically, after discharging, this cell or battery can be recharged by applying an electrical current to its terminals. Certain of these batteries or cells can be recharged hundreds or thousands of times such as, for example, a lead-acid battery. These batteries or cells operate as a galvanic cell during discharge and as an electrolytic cell during charge. Accordingly, the anode is the negative electrode during discharging, while the anode becomes the positive electrode during charging.
"Self discharge", as used herein, means a slow discharging of a battery without being connected to an external load. These types of reactions are typically caused by impurities and/or side reactions (i.e., reactions occurring other than the primary reaction) within a cell.
"Shelf life", as used herein, means a time period for non-rechargeable batteries storage whereby electrochemical reactions of suitable magnitude are still capable of occurring.
"Sodium/Sulfur battery" or "Sodium/Sulfur cell", as used herein, means cells that utilize molten sodium metal as the anode, molten sulfur as the cathode and a solid aluminum oxide electrolyte. The overall cell reaction is2Na+xS=NaSx.
"Solid oxide fuel cell" or "SOFC", as used herein, means a solid oxide is used as an electrolyte in this fuel cell. Suitable solid oxides, typically ceramic materials, include the following materials: yttrium stabilized zirconia; scandium doped zirconia; samarium doped ceria; gadolinium doped ceria; yttrium doped ceria; calcium doped ceria; lanthanum strontium gallium magnesium; bismuth yttrium oxide; strontium cerate; and barium cerate. The yttrium stabilized zirconia solid electrolytes are the most common of the electrolytes used. These fuel cells operate at temperatures of up to about 1000° C. These fuel cells are typically formed in the shape of tubes.
"Sonoelectrochemistry", as used herein, means electrochemical phenomena and processes occurring under the influence of sound waves.
"Spectral catalyst", as used herein, means electromagnetic energy which acts as a catalyst in a cell reaction system, for example, electromagnetic energy having a spectral pattern which affects, controls, or directs a reaction pathway.
"Spectral conditioning catalyst", as used herein, means electromagnetic energy which, when applied to a conditionable participant to form a conditioned participant, assists the conditioned participant to act as a catalyst in a cell reaction system, for example, electromagnetic energy having a spectral conditioning pattern which causes the conditioned participant to affect, control, or direct a reaction pathway in a cell reaction system when the conditioned participant becomes involved with, and/or activated in, the cell reaction system.
"Spectral conditioning environmental reaction condition", as used herein, means at least one frequency and/or field which simulates at least a portion of at least one conditioning environmental reaction condition.
"Spectral conditioning pattern", as used herein, means a pattern formed by one or more electromagnetic frequencies emitted or absorbed after excitation of an atom or molecule. A spectral conditioning pattern may be formed by any known spectroscopic technique.
"Spectral energy catalyst", as used herein, means energy which acts as a catalyst in a cell reaction system having a spectral energy pattern which affects, controls, and/or directs a reaction pathway.
"Spectral energy conditioning catalyst", as used herein, means conditioning energy which, when applied to a conditionable participant, assists a conditionable participant, once conditioned, to act as a catalyst in a cell reaction system, the conditioned participant having a spectral energy pattern which affects, controls and/or directs a reaction pathway when the conditioned participant becomes involved with, and/or activated in, the cell reaction system.
"Spectral energy conditioning pattern", as used herein, means a pattern formed by one or more conditioning energies and/or components emitted or absorbed by a molecule, ion, atom and/or component(s) thereof and/or which is present by and/or within a molecule, ion, atom and/or component(s) thereof.
"Spectral energy pattern", as used herein, means a pattern formed by one or more energies and/or components emitted or absorbed by a molecule, ion, atom and/or component(s) thereof and/or which is present by and/or within a molecule, ion, atom and/or component(s) thereof. For example, the spectral energy pattern could be a series of electromagnetic frequencies designed to heterodyne with reaction intermediates, or the spectral energy pattern could be the portion of the actual spectrum emitted by a reaction intermediate.
"Spectral environmental reaction condition", as used herein, means at least one frequency and/or field which simulates at least a portion of at least one environmental reaction condition in a cell reaction system.
"Spectral pattern", as used herein, means a pattern formed by one or more electromagnetic frequencies emitted or absorbed after excitation of an atom or molecule. A spectral pattern may be formed by any known spectroscopic technique.
"Targeting", as used herein, means the application of energy to a cell reaction system by at least one of the following spectral energy providers: spectral energy catalyst; spectral catalyst; spectral energy pattern; spectral pattern; catalytic spectral energy pattern; catalytic spectral pattern; applied spectral energy pattern; and spectral environmental reaction conditions, to achieve direct resonance and/or harmonic resonance and/or non-harmonic heterodyne-resonance with at least one of the following forms of matter: reactants; transients; intermediates; activated complexes; physical catalysts; reaction products; promoters; poisons; solvents; physical catalyst support materials; reaction vessels; and/or mixtures or components thereof, said spectral energy provider providing energy to at least one of said forms of matter by interacting with at least one frequency thereof, to produce at least one desired reaction product and/or at least one desired reaction product at a desired reaction rate.
"Throwing power", as used herein, means the ability of an electroplating system to produce a uniformly thick deposit on a substrate surface.
"Transient", as used herein, means any chemical and/or physical state that exists between reactant(s) and reaction product(s) in a reaction pathway or reaction profile.
"Zinc air cell", as used herein, means a cell which uses a gas diffusion electrode, a zinc anode separated by an electrolyte and some form of mechanical separators. The gas diffusion electrode permits atmospheric oxygen to pass through. The oxygen is converted into hydroxyl ions and water and the hydroxyl ions travel through an electrolyte to the zinc anode. The hydroxyl ions react with zinc and zinc oxide is formed. The formation of zinc oxide creates an electrical potential.
"Zinc-carbon battery" or "Zinc-carbon cell", as used herein, means a battery or cell wherein the electrodes are comprised of zinc and carbon, respectively, with an acidic paste serving as the electrolyte.

This patent is subject to a terminal disclaimer.

Optimizing reactions in fuel cells and electrochemical reactions


A detection unit of a charged particle imaging system includes a multi type detection subunit in the charged particle imaging system, with the assistance of a Wien filter (also known as an E×B charged particle analyzer). The imaging system is suitable for a low beam current, high resolution mode and a high beam current, high throughput mode. The unit can be applied to a scanning electron inspection system as well as to other systems that use a charged particle beam as an observation tool.

In order to lower the costs and improve the performance of ICs (integrated circuits), the design nodes of ICs should be made smaller. Shrinking of the design nodes to 22 nm or even smaller, however, makes the defect inspection tool, such as an optical system, less able to detect the defects, owing to the optical resolution of light sources used being equal to or larger than the defect dimension. For advancing resolution in defect inspection, a more applicable inspection tool, such as an e-beam inspection tool, is provided for semiconductor process inspections. Further, in a VC (voltage contrast) mode of inspection the e-beam inspection tool can inspect for under-layer defects, the performance of which is almost impossible for current-day optical inspection systems to match. Hence, the e-beam inspection tool has become more important in the context of semiconductor processes.
Nevertheless, due to restrictions of the e-beam system per se, throughput thereof is much lower than that of optical systems. In order to increase throughput and VC inspection, larger currents, such as several hundreds nano-amperes (nA), are applied in the e-beam inspection systems. On the other hand, to increase the inspection resolution of the e-beam inspection system, small currents, such as several tens of pico-amperes (pA), are applied instead.
Up to the present day, there still is no single e-beam system that can handle both large current and small current inspections. A suitable means of using different e-beam systems for variant purposes while inspecting would definitely require more space (at least double the space) and more costs for the inspection. Therefore, there is a need for a new design of an e-beam inspection tool having the capability to handle both the large and small beam currents for handling both high resolution and high speed requirements.

Charged particle beam detection unit with multi type detection subunits


A method for forming a gate, which can improve the etching uniformity of the sidewalls of the gate, includes the following steps: forming a dielectric layer on a semiconductor substrate; forming a polysilicon layer on the dielectric layer; etching the polysilicon layer; performing an isotropic plasma etching process on the etched polysilicon layer by using a mixed gases containing a fluorine-based gas and oxygen gas; and cleaning the semiconductor substrate subjected to the isotropic plasma etching process, thereby forming a gate. The present invention further provides a method for forming a shallow trench isolation region, which can improve the filling quality of a subsequent spacer and the electrical properties of the resultant shallow trench isolation region, and a method for planarizing an etched surface of silicon substrate, which can improve the etching uniformity of the surface of silicon substrate.

The manufacturing of a gate is a key step for a process for forming a semiconductor device, since the gate conventionally has a minimal physical dimension in the process of manufacturing a semiconductor device, i.e. the width of the gate conventionally is a critical dimension of the semiconductor device.
In the prior art, a method for forming a gate conventionally includes the following steps: forming a dielectric layer 20 on a semiconductor substrate 10, as shown in FIG. 1a; forming a polysilicon layer 30 on the dielectric layer 20, as shown in FIG. 1b; forming an etched resist layer 40 on the polysilicon layer 30, as shown in FIG. 1c; etching the polysilicon layer 30 by using the etched resist layer 40 as mask to form a gate 32.
As the critical dimension of the device decreases gradually, how to precisely controlling the width of a gate has become a primary problem interested by the skilled in the art. Many attempts has been tried to resolve this problem, for example, the Chinese patent publication No. CN 1855372A (disclosed on Nov. 1, 2006) discloses a method for forming a gate, in which a precise controlling for a width of the gate is achieved by avoiding horns generated on a top surface of the gate.
However, it is found in practice that a roughness 34 formed on the sidewalls of a gate also can affect the precise controlling for a width of the gate negatively in addition to the horns on the top surface, as shown in FIG. 1e. Conventionally, the roughness 34 is regarded to be formed due to a non-uniform etching during the process for forming a gate. The problem of improving the etching uniformity of sidewalls of a gate has attracted more attentions in the art.
Furthermore, shallow trench isolation (STI) process is a key process for isolating between active regions formed on a semiconductor substrate as the decrease in critical dimension of a device. The profile character of the shallow trench such as smoothness of the sidewalls and bottom surface of the shallow trench can facilitate to improve a precise controlling for the width and depth of the shallow trench isolation region, and in turn, a precise controlling for the width and depth of the shallow trench isolation region can facilitate to improve the filling quality of a subsequent spacer and the electrical properties of the resultant shallow trench isolation region.
In the art, a method for forming a shallow trench isolation region includes the following steps: forming an etched passivation layer 60 on a silicon substrate 50, as shown in FIG. 2a; etching a portion of the silicon substrate 50 by using the etched passivation layer 60 as a mask to form a shallow trench 52, as shown in FIG. 2b; and filling the shallow trench to form a shallow trench isolation region. A device active region has been defined in the silicon substrate.
However, it is found in practice that a roughness 54 is easily formed on the sidewalls of the shallow trench and it can affect the precise controlling for a width and depth of the shallow trench negatively, as shown in FIG. 2c. The roughness 54 is conventionally regarded to be formed due to a non-uniform etching during the process for forming the shallow trench. How to improve the etching uniformity of sidewalls and bottom surface of a shallow trench has attracted more attentions in the art.

Methods for forming a gate and a shallow trench isolation region and for planarizing an etched surface of silicon substrate

Semiconductor Manufacturing International (Shanghai) Corporation


A stabilized aqueous, thermosetting coating composition substantially free of acid cure catalysts comprises a mixture of an ion-exchanged reactive function emulsion polymer and a glycoluril derivative adapted to coreact and crosslink the functional polymer where certain cations are added to the ion-exchanged mixture to provide a pH of the mixture between 2 and 5.

This relates to commonly assigned U.S. Ser. No. 943,794 filed Dec. 19, 1986, now U.S. Pat. No. 4,728,680 and the disclosure of said application incorporated herein by reference. This invention pertains to emulsion coatings treated by cation exchange where the emulsion polymers contain hydroxyl or carboxyl groups but are free of amine groups. The stable reactive coating is based on ion-exchange of a water dispersed mixture of glycoluril resin and acrylic emulsion polymer containing carboxyl and/or hydroxyl groups but free of amine groups, where certain cation salts are added to increase the pH of the coating without adversely affecting the thermosetting cure of the coating.
Prior to this invention, glycoluril cured thermosetting emulsions were produced from non-ionic and acidic surfactants and generally required high levels of such surfactants. Anionic salt surfactants cause a detriment to the curing reaction while pigmentation of such glycoluril and emulsion mixtures cause undesirable flocculation during the pigment grind step and subsequent let-down to produce pigmented mixtures.
Prior art U.S. Pat. Nos. 4,442,257 and 4,444,941 teach the use of certain acrylic latexes crosslinked with either tetramethylol glycoluril (TMGU) or dihydroxy dimethylol ethylene urea (DDEU) for low-temperature curing coatings. Rapid cure is achieved with these products by adding from 1.5% to 3.5% by weight of a 40% solution of paratoluene sulfonic acid where a package pH of about 1.0 to 2.0 results. Stability of these catalyzed products ordinarily is limited to 1-5 days at room temperature, and much less at elevated temperatures. Hence, the acid catalyst must be added at the time of use. Cured films of such polymeric mixtures often exhibit certain water sensitivity due to residual catalyst in the cured films. Without the acid catalysts, however, the coating has no solvent or water resistance unless baked at extremely high temperatures.
Abbey (U.S. Pat. No. 4,525,260) discloses a cationic latex for cathodic electrocoating and specifically includes amine monomers. The reference latex is based on acrylic monomers copolymerized with amine monomers, such as N,N-dimethyl-2-aminoethyl methacrylate, and catalyzed with an azo catalyst. Abbey subsequently treats the cationic latex with an ion exchange resin but to specifically remove amino monomers and amino initiator fragments. Hence, the reference is specifically directed to removing amino fragments introduced in the emulsion process. As noted below, amine latexes are not operative in this invention in that amine groups block coreactivity with a glycoluril cross-linker and inhibit the cure.
In commonly assigned U.S. Ser. No. 943,794 filed Dec. 12, 1986, low temperature cure emulsion polymers particularly useful in paint coatings are disclosed based on a thermosetting polymeric binder composition comprising a functional addition polymer containing functional hydroxyl or carboxyl groups, but free of amine groups, and a glycoluril derivative adapted to be coreactive with the functional polymer. The functional polymer and preferably the glycoluril derivative are treated with an ion exchange process step to remove undesirable cations. The resulting resin provides a highly desirable low temperature cure paint coating adapted to thermoset without the addition of undesirable acid catalysts. However, it has been found that cation exchanged polymeric mixtures based on functional emulsion polymers adapted to be coreactive with glycoluril derivatives and pigmented with considerable amounts of conventional commercial titanium dioxide exhibit an upward pH drift of as much as one pH unit within a few days after cation exchange of the polymeric binder and/or the paint coating, which does not seem to materially effect the stability or low heat cures, but nevertheless limits the commerical utility of process to darker color paints.
It now has been found that cation-exchanged polymeric compositions, wherein the great majority of soluble cations have been replaced by protons, the composition comprising functional emulsion polymers and coreactive glycoluril used in paint coatings can be substantially improved by the addition of additive amounts of certain cation salts to adjust the pH without loss of cure and thermosetting properties. The use of certain cation salts to adjust the pH upwardly provides considerable flexibility to paint formulations including versatility with respect to light colored pigmented paint coatings. The addition of various mono- and polyvalent cation salts to cation-exchanged reactive latex/glycoluril blends cause an increase in the pH of the blend with no detrimental effect on cure properties. By using this technique, the pH of cation-exchanged glycoluril coatings may be adjusted to reduce the possibility of hydrolysis or degradation of certain paint components and/or simplify pigmentation, for example, without inhibiting the crosslinking reaction. A coating pH above 2 and preferably above 3 effectively avoid corrosion problems when the coating is applied to steel substrates. These and other advantages will become more apparent by referring to the detailed description and illustrative examples.

Process for producing low temperature cure emulsions