Surface Force Measurement and Characterization of Functionalized Molecular Assemblies

This article reviews applications of surface forces measurement for characterizing interactions of molecular assemblies with overview given in Table 1. Measurement techniques using a surface force apparatus and a colloidal probe atomic force microscope described in a concise manner, and the results of detailed researches on functionalized surfactant assemblies are presented. 1) Surface forces measurement provided evidence for spontaneous vesicle formation of an ammonium surfactant with an acetate counterion. 2) The mechanism of fusion and aggregation of surfactant vesicles in the presence of salt (NaCl) was clarified. 3) Interactions between bilayers of various biological phospholipids were found to be attractive van der Waals and repulsive steric hydration forces in pure water and monovalent salt solutions. 4) Hydrogen-bonding interactions between glycine head groups were directly demonstrated. 5) Interactions between LB films of metal-chelating lipids ; pH dependence reflected different protonation states of iminodiacetic acid groups, and Cu2+ complexation with them. 6) The effects of surfactant on the particle bubble interactions between hydrophilic and hydrophobic silica particles and an air bubble were examined .