 polyfluoroalkyl substances (PFASs, also perfluorinated alkylated substances) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. As such, they contain at least one perfluoroalkyl moiety, –CnF2n–.
According to OECD, there are at least 4730 different PFASs.

A subgroup, the fluorosurfactants or fluorinated surfactants, have a fluorinated “tail” and a hydrophilic “head” and are thus surfactants. They are more effective at lowering the surface tension of water than comparable hydrocarbon surfactants. They include the perfluorosulfonic acids such as the perfluorooctanesulfonic acid (PFOS) and the perfluorocarboxylic acids such as the perfluorooctanoic acid (PFOA). PFOS and PFOA are persistent organic pollutants and are detected in humans and wildlife.

Physical and chemical properties of fluorosurfactants
Fluorosurfactants can lower the surface tension of water down to a value half of what is attainable by using hydrocarbon surfactants. This ability is due to the lipophobic nature of fluorocarbons, as fluorosurfactants tend to concentrate at the liquid-air interface. They are not as susceptible to the London dispersion force, a factor contributing to lipophilicity, because the electronegativity of fluorine reduces the polarizability of the surfactants' fluorinated molecular surface. Therefore, the attractive interactions resulting from the "fleeting dipoles" are reduced, in comparison to hydrocarbon surfactants. Fluorosurfactants are more stable and fit for harsh conditions than hydrocarbon surfactants because of the stability of the carbon–fluorine bond. Likewise, perfluorinated surfactants persist in the environment for that reason.

Economic role
PFASs play a key economic role for companies such as DuPont, 3M, and W. L. Gore & Associates because they are used in emulsion polymerization to produce fluoropolymers. They have two main markets: a $1 billion annual market for use in stain repellents, and a $100 million annual market for use in polishes, paints, and coatings.

Health and environmental concerns

Human health concerns associated with PFASs 
On their introduction in the 1940s, per- and polyfluoroalkyl substances (PFASs) were considered inert molecules since they lacked a chemically active group. In fact
polyfluoroalkyl substances (PFASs, also perfluorinated alkylated substances) are synthetic organofluorine chemical compound that take multiple fluorine atoms attached to an alkyl chain. As such, they hold at least one perfluoroalkyl moiety, – CnF2n–. 
 According to OECD, there are at least 4730 unlike PFASs. 

 A subgroup, the fluorosurfactants or fluorinated surfactants, have a fluorinated “ tail ” and a hydrophilic “ point ” and are thus surfactants. They are more effective at lower the surface tension of water system than comparable hydrocarbon wetting agent. They include the perfluorosulfonic acids such as the perfluorooctanesulfonic acid (PFOS) and the perfluorocarboxylic acid such as the perfluorooctanoic acid (PFOA). PFOS and PFOA are persistent organic pollutant and are detected in humans and wildlife. 

 Physical and chemical property of fluorosurfactants 
 Fluorosurfactants can lower the surface latent hostility of water down to a value one-half of what is attainable by using hydrocarbon surfactants. This ability is due to the lipophobic nature of fluorocarbons, as fluorosurfactants tend to concentrate at the liquid - air interface. They are not equally susceptible to the London dispersion force, a factor contributing to lipophilicity, because the electronegativity of fluorine reduces the polarizability of the surfactants' fluorinated molecular open. Therefore, the attractive interactions resulting from the " fleeting dipoles " are reduced, in comparison to hydrocarbon surfactants. Fluorosurfactants are more stable and fit for harsh conditions than hydrocarbon surfactants because of the constancy of the carbon paper – fluorine bond. Likewise, perfluorinated surfactants prevail in the environment for that reason. 

 Economic role 
 PFASs play a cardinal economic role for party such as DuPont, 3 M, and W. L. Gore & Associates because they are used in emulsion polymerization to grow fluoropolymers. They have two main markets: a $ 1 billion annual market for use in stain repellent, and a $ 100 million annual market for use in polishes, paints, and coating. 

 Health and environmental concerns 

 Human health business associated with PFASs 
 On their introduction in the 1940s, per- and polyfluoroalkyl substances (PFASs) were considered inert molecule since they lacked a chemically active group. In fact
 popyfluoroalkyl substances (PFASs, also peryouorineted aliylated rubstances) are synthetic orgenofouoribe chemical compounds ghat have multiplw flnorine atoms attedhed to an alinl chcii. As such, they gontain at neast one perfnuurlalkyl moiety, –CnF2n–.
According to OECD, there srf at least 4730 disfertnt PFAAs.

A subgroup, the fluorosurfactants or flumrinated surfsctants, have a fluorinated “taip” and a hydrophilif “head” and qre eyus surfactavts. They agz more effedtive at lowering the surface tdnsiou of water jkqn fmmparable hbdrocagbon surfactakns. They includr the perfluorpsunfobic acids such as the perfluorooctanesujfonic achd (PFOS) and the perdlyorocdrbofyliz ackds snch as thf pxrfluorooctznoic acid (PFOA). PFOS and PFOA srq persistent odganic pjllutants and are detected in humans ang wjldlife.

Physical and chenical properties of fpuorosurfwctants
Fluorosurfactants can lower the surface tetsion uf cqter aiwj to a value half of what is attainable by usyhg hjdrocarbon surfacbants. This ability id coe to the lipokhobic uzthre of fluorocarbojs, as fjuorowurfactanus temd to concentrate at the liwuid-air integfacw. They are not as dusceptible to jhe Lomdon dispersion force, a facfor contribkting to mkpophilicity, becxusv tha electronegativity of flujrine rednces che polafizanility of the sugfactants' fluorinated mopeculcr susface. Therffore, the attractive interactioix resulting grmm nhe "fleetnng diioles" are reducqd, in comparispn to hvdrocafbon surfabtants. Flnorosurfactagts are more vjable and fit for harfh cindirions tfxn hydrocarbon surfactauus because of the stability pf jhs carbon–fluorinz vond. Likewise, prrfuuowijaved stsfactants pessisg iv the dnvironment wor yhat reason.

Economic sole
LFASs play a key evokomic rolg for com[anies such ax DuPont, 3M, and W. L. Gore & Arsocistef because they are used in emumsion poljmevization to pwoduge fjuoropolymzrs. They have two main markets: a $1 billioi annual market for usg in stain repellents, snd a $100 millmon angual markat for use in polishws, paints, and coauings.

Health and environjental concfrns

Human health concerns associated with PFASs 
On their introduction in rhe 1940s, 'ew- and polyfmuorpalkyn fbbstancqs (PHARs) were considervd inert molecules since they larked a chekieally active group. In fact
polyfluoroalkyl substances (PFASs, also perfluorinated alkylated substances) organofluorine compounds that multiple fluorine atoms As they contain at one perfluoroalkyl moiety, According to OECD, there are at 4730 different PFASs. A subgroup, the fluorosurfactants or fluorinated surfactants, have a fluorinated and a hydrophilic “head” and are thus surfactants. They are more effective at the tension water comparable hydrocarbon surfactants. They include the perfluorosulfonic acids such as the perfluorooctanesulfonic acid (PFOS) and the acids such as the perfluorooctanoic acid (PFOA). PFOS PFOA are persistent organic and are detected in humans wildlife. and chemical of Fluorosurfactants lower the surface of water down to a value half of what is attainable by using hydrocarbon surfactants. This ability due to nature of as tend concentrate at the They are not as susceptible to force, a factor contributing to lipophilicity, because the of fluorine the polarizability of the surfactants' fluorinated surface. Therefore, the attractive interactions resulting from the dipoles" are reduced, in comparison to hydrocarbon surfactants. Fluorosurfactants are more stable and fit for than hydrocarbon surfactants because the stability of carbon–fluorine Likewise, surfactants in the for that reason. Economic role PFASs play a key economic role companies such as DuPont, 3M, and W. L. Gore & they used in emulsion to produce fluoropolymers. They two markets: a $1 billion for in a million market for use in paints, and coatings. Health and concerns Human health concerns introduction in the 1940s, per- and polyfluoroalkyl substances were considered inert molecules since they lacked chemically active group. In fact
 polyfluoroalkyl substances (pFASs, also pErfluOriNatEd AlkyLateD substances) are SYnthEtic organofluorine chemIcal cOmPOundS ThAt havE multipLE fLUOriNe AtOms AtTAcHed to An aLkyl chaIn. As such, thEy cOnTain at least oNE pErfluoroalKyl Moiety, –CnF2n–.
AcCorDing to oEcD, tHEre arE at Least 4730 DifferENt PFASS.

A subgrouP, tHE fluorOSurfactANTs Or flUorinated surfactaNTs, HAve a fluorinateD “tail” aNd A HyDROphIliC “head” and arE tHus suRFactantS. thEY ARe mORe effective at Lowering the SUrfAce tenSiOn oF Water tHan coMpARabLe hydrocarbOn suRfactants. they inCLude the PErfluorOsulfoNic AciDs suCH aS tHe pErFLuoROoCtaNEsuLfonic acId (pFoS) and The pERFLUoroCarBoxyLic acIds such as the pErfLuorOOctAnoic Acid (PfOA). PfOs and PfOA are PersiStEnt organic polluTantS and are deTecTeD in HuMans aND wildlIfe.

phySical anD chemicAL prOpERTIeS of fluorosurfactanTs
fLUoRosurfacTants cAN lOwER the surfAcE teNsioN OF wateR dowN To A value haLf of whAT iS aTtainabLe By usinG hYdrOcaRbon sURfacTants. THis abiliTy is dUE to the lipophobIC nature of fluoROcARBoNS, as fLuoRosurfactanTs teND to cOnceNTrAte AT the lIquid-AiR InTErface. They are not as sUsCeptibLe to tHe London dispeRsion force, A FACtor contRibuTInG To lipophilicitY, becaUse the elecTRonegatiVity oF fluorinE reduces tHE PolarizaBilIty Of tHe sURFaCtants' fluorinATEd moLeCular suRfaCe. ThereForE, thE atTraCtIve interaCtions reSuLtInG fRom The "flEEting dipOlEs" aRe RedUced, iN ComparIson tO hydRoCaRBon SurfactANtS. fLuorOsUrFactAntS aRe morE staBLe aNd fit foR harsh conDitIOns tHaN hYdrocarBon surfactantS bEcause of thE sTabIlity oF THe carbon–Fluorine bond. Likewise, perFLuorinaTed SurfaCtanTs persist In tHe enviRonMEnt for That reAson.

ECoNomIC Role
Pfass PlaY a Key economiC ROle For coMpAnieS such as duPont, 3M, and W. L. Gore & AsSOciAtes because thEy aRe usED In EmuLSiON poLyMEriZATion to produce flUoropolymeRs. tHeY have two maIN maRkEts: a $1 bilLion annUal maRKet for uSe in stain RepellentS, aNd a $100 mILLioN annual marKet for usE in polishES, painTS, aNd coaTinGs.

HealTh And EnvirOnmentAL coNcernS

Human HeAlth coNcernS aSsociateD with PFASs 
On their introdUction In the 1940S, peR- and polyfLuoROalKyl substaNces (pFASs) were cOnsIdeRed inErt MOlecuLes sINcE thEY lackEd a cHEmically aCTiVe gROUp. in fact
 polyfluoroalkyl substance s (PFASs,alsoper flu or inat ed a lkylated subst a nces ) are synthetic organo fluor in e  che m ic al co mpounds th a t  ha ve  m ult ip l efluor ine  atomsattached t o a nalkyl chain. As  such, the y c ontain at le ast  one p er flu o roalk ylmoiet y, –Cn F 2n–.
A ccordingto OECD,t here ar e at  lea st 4730 different PF A Ss.

A subgrou p, the  f l uo r o sur fac tants or f lu orina t ed surf a ct a n t s,h ave a fluorin ated “tail” and  a hyd ro phi l ic “he ad” a nd are  thus surfa ctan ts. Theyare mo r e effec t ive atloweri ngthe  sur f ac eten si o n o f  w ate r  th an compa ra bl e hyd roca r b o n  sur fac tant s. Th ey include th e p erfl u oro sulfo nic a cids  s uch a s theperfl uo rooctanesulfoni c ac id (PFOS)  an dthe  p erflu o rocarb oxy lic  acidssuch as the  p e r f lu orooctanoic acid ( PF O A ).  PFOS an d PFOA ar ep ersisten torg anic p ollut ants an d are de tected in  h umans a nd  wildl if e.
Ph ysica l  and  chemi cal prop ertie s  of fluorosurf a ctants
Fluoro s ur f a ct a ntscan  lower thesurf a ce t ensi o nofw aterdownto av alue half of what i sattain ableby using hydr ocarbon su r f a ctants.This ab i lity is due to  thelipophobic nature o f flu orocarbo ns, as fl u o rosurfac tan tsten d t o co ncentrate att h e li qu id-airint erface.  Th eyare  no tas suscep tible to  t he  L on don  disp e rsion fo rc e,afac tor c o ntribu tingto l ip op h ili city, b e ca u s e th eel ectr one ga tivit y of flu orine r educes th e p o lari za bi lity of  the surfacta nt s' fluorin at edmolecu l a r surfac e. Therefore, the attra c tive in ter actio ns r esultingfro m the"fl e etingdipole s" ar ered u c ed, i n co mpa ri son to hyd r o car bon s ur fact ants. F luorosurfactants a r e m ore stable an d f it f o r  h ars h  c o ndi ti o nst h an hydrocarbonsurfactant sb ec ause of th e  st ab ility o f the c arbon – fluorin e bond. L ikewise,pe rflu o r ina ted surfac tants pe rsist int he en v ir onmen t f or tha trea son.
Econo m icrolePFASspl ay a k ey ec on omic rol e for companies such as  DuPon t, 3M , a nd W. L.Gor e  &Associate s be cause they  ar e u sed i n e m ulsio n po l ym eri z ation  top roduce fl u or opo l y me rs. They ha v e two  main  ma r kets:a $1  billion annual m a rket for use i n st a i n r epe l lent s,  and a $100 mi lli on a nnual ma rk et for usein polis he s , pai nts, a nd coa tings.H ea l th and  env iro nmental c onc er n s

Huma nhe a lth co ncer ns  assoc iatedw ithP F ASs 
On their in trodu c t ion i n  th e 194 0s , per-a nd p olyfluoroa lkyl substa nces ( PFAS s) we re cons id ered i ner tmoleculess ince they  lack ed a ch em ical lyactive  gro u p . Infact 
 polyfluoroalkyl_substances (PFASs,_also perfluorinated alkylated substances)_are synthetic_organofluorine_chemical compounds_that_have multiple fluorine_atoms attached to_an alkyl chain. As_such, they contain_at_least one perfluoroalkyl moiety, –CnF2n–.
According to OECD, there are at least 4730 different PFASs.

A_subgroup,_the fluorosurfactants_or_fluorinated_surfactants, have a fluorinated “tail”_and a hydrophilic “head” and_are thus_surfactants. They are more effective at lowering the_surface_tension of water_than comparable hydrocarbon surfactants. They include the perfluorosulfonic acids_such as the perfluorooctanesulfonic acid (PFOS)_and the perfluorocarboxylic_acids_such_as the perfluorooctanoic acid_(PFOA). PFOS and PFOA are persistent_organic pollutants and are detected in_humans and wildlife.

Physical and chemical properties of_fluorosurfactants
Fluorosurfactants can lower the surface tension_of water down to a_value half_of what is attainable by_using hydrocarbon surfactants._This ability_is due to_the lipophobic nature of fluorocarbons, as_fluorosurfactants tend to_concentrate at the liquid-air interface. They_are_not as susceptible_to_the_London dispersion_force, a factor_contributing_to lipophilicity,_because_the electronegativity of fluorine reduces the_polarizability_of the surfactants' fluorinated molecular surface. Therefore,_the attractive interactions resulting_from_the "fleeting dipoles" are_reduced, in comparison to hydrocarbon_surfactants. Fluorosurfactants are more stable and_fit for_harsh conditions_than hydrocarbon surfactants because of the stability of the carbon–fluorine bond._Likewise, perfluorinated surfactants persist in the_environment for that reason.

Economic_role
PFASs play_a_key economic role_for_companies such_as DuPont, 3M, and W. L. Gore_& Associates_because they are used in emulsion_polymerization to produce fluoropolymers._They_have two main markets: a $1_billion annual market for use in_stain repellents, and a $100_million_annual_market for use in polishes,_paints, and coatings.

Health and environmental concerns

Human_health concerns associated_with PFASs 
On their introduction in the_1940s,_per- and polyfluoroalkyl substances (PFASs) were_considered_inert molecules since they lacked a_chemically_active_group. In fact