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# Interfacial water, adsorbate negative plate, "exclusion zone" dielectric, and hydronium-rich bulk water positive plate
Water at hydrophilic surfaces organizes into layers similar to what you see in a capacitor: a positive and negative plate separated by a dielectric. The positive and negative regions form in a way similar to what happens at semiconductor junctions, where charge carriers have an asymmetry in how mobile they are and one of them moves away by diffusion, forming an electric field. The water adsorbs to the hydrophilic surface with 2-3 atomic layer, and as it auto-ionizes by contact with the bulk water, the hydroxide ion is immobile (stuck within the adsorbate) while the hydrogen ion is free to move by jumping from water to water. The separation of charge by this effect generates an electric field, and this electric field polarizes the adjacent water - the dielectric . As the water molecules become aligned with the electric field they prefer to form an ordered structure (visible in diffraction photographs from McGeoch, 2008). In the ordered adjacent water, particles do not dissolve as well, it tends to exclude particles and push them outwards, and scientists who studied it have used the term exclusion zone to refer to this water. The low solubility for particles also includes hydrogen ions, thus the exclusion zone is an insulator for hydrogen ions, and this reduces the tendency for the OH- in the adsorbate and H+ in the bulk water to recombine. The polarization of the water molecules partly cancel out the electric field (this is what a dielectric does), which lets the H+ diffuse further out, lowering the tendency to recombine even more. The result is an extremely high degree of ionization in the adsorbate. The ionization is so high that the adsorbate (which is initially ice-like) loses so much hydrogen ions that it can no longer separate the honeycomb sheets, and these collapse against one another, and shift sideways relative to one another by half an oxygen atom (the electrostatically favourable structure as the oxygens then face hydrogens). This phase has 50% ionization, it is chemically (H3O2-)n. It is what Gerald Pollack calls the fourth phase .
# References
McGeoch, J. E., & McGeoch, M. W. (2008). Entrapment of water by subunit c of ATP synthase. Journal of the Royal Society, Interface, 5(20), 311 318. https://doi.org/10.1098/rsif.2007.1146