Adsorbate–liquid diffusion potential organizes an ionic water lattice.

At a hydrophilic surface, water adsorbs in a few molecular layers. Autoionization between that adsorbate and the adjacent liquid releases H⁺ into the liquid and leaves OH⁻ behind in the film. An electric field arises. The field autoionizes the water next to the adsorbate, which orders into an ice-like ionized lattice of stretched OH⁻ / H₃O⁺ pairs — H₃O⁺ toward the surface, OH⁻ away.