Multivalent-ion-mediated stabilization of hydrogen-bonded multilayers

Abstract

Hydrogen-bonding interactions are an important alternative to electrostatic interactions for assembling multilayer thin films of uncharged components. Herein, a new method is reported for rendering such films stable at pH values close to physiological conditions. Multilayer films based on hydrogen bonding are assembled by the alternate deposition of poly[(styrene sulfonic acid)-co-(maleic acid)] (PSSMA) and poly(N-isopropylacrylamide) (PNiPAAm) at pH 2.5. The use of PSSMA results in multi-layers that contain free styrene sulfonate groups, as these moieties do not interact with the PNiPAAm functional groups. Subsequent infiltration of a multivalent ion (Ce4+ or Fe 3+) leads to an increase in ..