Sum Frequency Generation (SFG) Studies on the Interfacial Structure of Organic Thin Films

Abstract

A highly surface-sensitive vibrational spectroscopy, sum frequency generation (SFG), has been employed to investigate the interfacial structure of the Langmuir-Blodgett (LB) thin films on solid substrates. The SFG measurements demonstrate that the molecular structures at the surface layer of the even-numbered LB films of stearic acid considerably change both in air and in solution when Cd²⁺ cations are present. A flip-over model is proposed to explain the Cd²⁺-induced surface reorganization process.