Structural characterization of a polymer monolayer on a solid surface

A Langmuir-Blodgett monolayer of poly(octodecylmethacrylate) has been formed on a water surface and transfered to a solid substrate. The polymer was deposited onto a purified water subphase from a dilute (0.5-0.05 mg ml-1) solution in dichloromethane and the solvent allowed to evaporate. After several cycles of compressing the monolayer and allowing it to expand, the pressure-area isotherm was found to be completely reproducible up to a pressure of approximately 35 mN m-1. This comb-like polymer could be transferred to a solid hydrophilic surface as either a single monolayer with the polar heads down and aliphatic tails up, or as a multilayer structure. IR transmission, and reflection at grazing incidence, gave anisotropic spectra, indicating an orientation of the methacrylate and hydrocarbon side-chains relative to the surface. Bands attributable to backbone and side-chain vibrations have also been identified and were used to determine the orientation of the respective groups relative to the surface. All these results provide a molecular picture of the polymer topography. © 1985.