New Monolayer Architecture Constructed by Competitive Hydrogen-Bonding Force and Compression Pressure Characterized by Infrared Multiple-Angle Incidence Resolution Spectroscopy

A unique monolayer that has a novel film architecture has been constructed by controlling a balance of hydrogen-bonding force and monolayer compression pressure, and the new film architecture has been characterized by infrared multiple-angle incidence resolution spectroscopy (MAIRS) that has recently been developed. The compound synthesized for the study consists of a single hydrocarbon chain and a headgroup that has three trans amide moieties. The limiting molecular area of the monolayer isotherm was approximately double that typically obtained for a single alkanoic-acid chain molecule, which suggested unusual film architecture. Then, the monolayer was transferred on a germanium substrate by the Langmuir-Blodgett film technique, and it was subjected to the infrared MAIRS analysis. The in-plane and out-of-plane mode spectra of MAIRS clearly suggested a flat alignment of interdigitated hydrogen-bonding networks and standing hydrocarbon chains with a disordered kink, which were totally consistent with a corresponding infrared reflection - absorption spectrum and the results of the isotherm measurement. The study suggests that the strongly correlated physical parameters are useful to develop a new film architecture.