Alternating maleic acid copolymers dissolved in aqueous solutions exhibit characteristic two-step dissociation profiles and pH-induced structural transitions in dependence on the comonomer unit. In extension of these findings, we analyzed a set of thin films of maleic acid copolymers (poly(octadecene-alt-maleic acid), POMA; poly(propylene-alt-maleic acid), PPMA; poly(styrene-alt-maleic acid), PSMA) randomly attached to planar glass surfaces by covalent binding. Streaming potential/streaming current measurements with a microslit electrokinetic setup (MES) were applied to determine zeta potential (zeta) and surface conductivity (K-sigma) data of the polymer layers in aqueous solutions of varied pH. The results confirmed the two-step dissociation behavior for all immobilized copolymers. A dramatic increase of K-o was observed for PPMA and PSMA-but not for POMA-layers at alkaline pH values, indicating that electrostatic repulsion of ionized groups controls the extension of the confined layers as long as hydrophobic interactions between the comonomers do not inhibit this effect. The isoelectric points (IEPs) show that for PPMA and PSMA layers the acidic functions dominate the interfacial charging and exhibit an enhanced acidity which can be explained by hydrogen bonds between the anion formed in the first dissociation and the proton of the adjacent undissociated group. In contrast, the layered POMA exhibits significantly less acidic IEP values due to the large comonomer. Hysteresis effects zeta of the versus pH profiles were observed for dissociation and association of the copolymers. This was explained by the reduced dynamics of structural transitions in the immobilized layers as compared to the dissolved molecules.