Investigation of the influence of the polyvinyl alcohol adsorption on the electrical properties of Al2O3-solution interface, thickness of the adsorption layers of PVA

The influence of acetate groups contained in polyvinyl alcohol (PVA) and it s molecular weight on the electrical properties of the Al2O3-polymer soluti on interface were examined. The main factors, having influence on the zeta potential and surface charge changes of Al2O3, were learned. It was shown t hat the change of the ion structure in the Stern layer depends considerably on the number of acetate groups (degree of hydrolysis) of the PVA macromol ecule and on the conformation of the polymer chain. By the comparison of th e determined values of the diffuse layer and surface charges a probable mec hanism was proposed, leading to zeta potential changes as a function of pH of the solution and PVA molecular weight. The calculated thickness of the a dsorption layers of PVA on the surface of Al2O3 confirmed the essential eff ect of acetate groups of PVA on its conformation at the surface layer of th e adsorbent. (C) 2000 Elsevier Science S.A. All rights reserved.