Electrokinetic properties of polymer and glass surfaces in aqueous solutions: experimental evidence for swollen surface layers.

Streaming potential and streaming current measuring techniques have been applied to polymer and glass surfaces to study solid/liquid interface electrical properties. The streaming current technique provides a reliable electrokinetic potential value, preexcluding surface conduction. A combination of both techniques results in experimental evidences for swollen, gel-like layers at (even apolar) polymer surfaces. Protons and hydroxide ions are the potential-determining ions indicated by the dependence of streaming potential on pH. Human serum albumin adsorption at a glass surface is discussed in terms of spatial distribution of the fixed macromolecular electric charges.