ESCA studies of sulfated polyethylene surfaces modified by adsorption of polyethyleneimine and colloidal silica particles

Abstract

The properties of the adsorbed layers resulting from adsorption of water-dissolved, cationic polyethyleneimine on sulfated (KMnO 4/conc H 2SO 4) polyethylene surfaces have been explored using ESCA. At pH ≳ 8 a comparatively thick adsorbed polyethyleneimine layer is formed whereas at pH ≲ 6 a thinner layer is obtained causing only a minor reduction of the sulfate S peak. From the angular dependence of the amine/protonated amine peak ratio we conclude that there is an accumulation of charged amine groups toward the sulfate surface. The extent of adsorption of colloidal silica particles (5–15 nm) to the sulfated and polyethyleneimine-treated surfaces depends mainly on the relative signs of charge, pH, and the size and surface charge density of the silica particles. A coherent silica film can be prepared using 6-nm silica particles either in acid form on sulfated polyethylene or in basic form on sulfated polyethylene further modified with polyethyleneimine.