The structure of adsorption layers of amphiphilic block and block‐like copolymers of poly(isobornyl acrylate) and poly(acrylic acid) on the surface of hydrophilic titanium dioxide and hydrophobic copper phthalocyanine (CuPc) pigments in an aqueous dispersion has been studied by the electrokinetic sonic amplitude (ESA) method. The electroacoustic behaviour of the polyelectrolyte block copolymer‐coated particles could be described in the context of the polymer gel layer theory. The polymer layer around the particles was found to be much thinner for CuPc as compared to the TiO₂ substrate. This is attributed to differences in the adsorption mechanism and the composition of the adsorption layer normal to the substrate surface. Adsorption models were established that consider effects of the copolymer structure.