Applying polymer chemistry to interfaces: Layer-by-layer and spontaneous growth of covalently bound multilayers

We report on the covalent layer-by-layer growth of multilayers of diphenylmethane derivatives where interlayer bonding is through a urea moiety. We demonstrate two routes to the growth of multilayer structures. The first method uses alternating copolymerization chemistry where isocyanate-containing monomers are reacted with amine-containing monomers, leading to growth that is controlled layer-by-layer. The second route uses isocyanate-functionalized monomers and hydrolysis to achieve layer growth, leading to spontaneous polymerization and less well-controlled layer growth. Both routes produce chemically identical structures as determined by C-13 NMR, FTIR, and UV-visible spectroscopies.