(B/Red) where the current is leaving, it will polarise anodically (potential will become more positive) and will corrode. This is due to polarisation which occurs opposite to the current direction. This theory is almost accepted in all classic and recent cathodic protection books, and NACE publications and standards, as explanation of corrosion and coating disbondment caused by DC interference between pipelines and different structures (e.g. cathodically protected or unprotected structures, railways and HVDC). This because it is more suitable for large-scale structures in highly resistive, heterogeneous environments where solution potential (Vs) plays a less pivotal role and the reactions are primarily concentrated only at the poles (where current enters and leaves). Case (C) The potential difference at each pole of the BPE (which may or may not be enough for electrochemical reactions). Note that the solution potential is not directly controlled by a power source (e.g. potentiostat) because it depends also on the solution composition. Therefore, for electrons to transfer to reduce species in the solution, the potential of the working electrode need to be set to a value more negative than of an electroactive molecule in the solution, and then – depending on the kinetics – electrons may transfer. In similar fashion, oxidation reactions occur. Also, according to Ohm’s law, the electric field and solution potential (Vs) will increase with increasing solution resistivity and the applied current at the outer-circuit. Utilisations The phenomenon of bipolar electrochemistry is known since the 1970s and is used in industry in some electrolytic reactors. The interest of the scientific community for this concept seems to increase a lot since Martin Fleischmann and co-workers demonstrated that water splitting was possible using micrometer-sized bipolar electrodes. Recently, several applications in such domains as synthesis of dissymmetrical micro- and nano-structures analytical chemistry material science, microelectronics and microobject propulsion have been developed. References Electrochemistry