The Effect of Polymer Substrate Surface Basicity on the Adsorption of a Cationic Polyacrylamide

The adsorption of a cationic polyacrylamide onto polytetrafluoroethylene, bisphenol-A based epoxy resins, and acrylate substrates was characterized with X-ray photoelectron spectroscopy (XPS) and dynamic contact angle measurement in water. Surface acidity-basicity was quantified via dynamic contact angle measurement in water, ethylene glycol, and diiodomethane. The epoxy resins exhibited intermediate surface basicity and adsorbed the most polyelectrolyte, suggesting that specific substrate-adsorbate acid-base interactions govern adsorption of the cationic polyacrylamide onto surfaces of low to intermediate basicity. In general polar interactions appear to dominate the adsorption process. Advancing contact angle measurements have yielded quantitative fractional surface coverage information for polymer-on-polymer adsorption comparable to that obtained via XPS. Copyright 1999 Academic Press.