Molecular layer-by-layer deposition of highly crosslinked polyamide films

A molecular layer-by-layer (mLbL) deposition process is demonstrated to synthesize conformal coatings of crosslinked polyamide. This process controls the rapid reaction of trimesoyl chloride and m-phenylene diamine, unlike interfacial polymerization techniques which produce rough films and poorly defined network structure. Layer-by-layer polyamide films appear structurally similar to interfacially polymerized films with a linear film growth rate of approximate to 0.9 nm per cycle. Films made by mLbL deposition show a 70-fold decrease in surface roughness as compared to a commercial, interfacially polymerized polyamide. Surface chemistry could be controlled based on which reaction step was performed last, leading to amine or carboxylic acid rich surfaces. With the ability to control chemical structure throughout the crosslinked network, this technique provides new routes to build polyamide films and improve analysis techniques for commercial applications such as reverse osmosis membranes. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 50: 168-173, 2012