The effect of polymer substrate surface basicity on the adsorption of a cationic polyacrylamide

The adsorption of a cationic polyacrylamide onto polytetrafluoroethylene, b isphenol-A based epoxy resins, and acrylate substrates was characterized wi th X-ray photoelectron spectroscopy (XPS) and dynamic contact angle measure ment in water. Surface acidity-basicity was quantified via dynamic contact angle measurement in water, ethylene glycol, and diiodomethane, The epoxy r esins exhibited intermediate surface basicity and adsorbed the most polyele ctrolyte, suggesting that specific substrate-adsorbate acid-base interactio ns govern adsorption of the cationic polyacrylamide onto surfaces of low to intermediate basicity, In general polar interactions appear to dominate th e adsorption process. Advancing contact angle measurements have yielded qua ntitative fractional surface coverage information for polymer-on-polymer ad sorption comparable to that obtained via XPS. (C) 1999 Academic Press.