Acid-Enhanced Interfacial Polymer Layer Growth

We report on the growth of interfacial multilayer structures formed from maleimide−vinyl ether alternating copolymers. The thickness and density of these polymer layers can be controlled by adding acid to the interlayer cross-linking reaction. We have demonstrated this control for several different interlayer cross-linking strategies, where amide, ester, urea, and urethane interlayer covalent bonds are formed. For all reactions, the addition of concentrated acid during polymer layer deposition resulted in a 2- to 4-fold increase in the loading density of the polymer relative to the acid-free reaction, depending on the acid used and its concentration. These findings are consistent with acid catalysis (HCl) and/or dehydration (H 2 SO 4 ).