Monolayers of Bolaform Amphiphiles: Influence of Alkyl Chain Length and Counterions

We have prepared self-assembled monolayers of novel cationic bolaform amphiphiles on negatively charged substrates. Most of these amphiphiles form smooth, defect-free monolayers which can be used to reverse the substrate surface charge and thus allow subsequent adsorption of anionic molecules and construction of multilayers. Atomic force microscopy, surface force measurement, and surface plasmon spectroscopy were combined to probe the molecular orientation and ordering, mechanical properties, and surface electrical properties of the monolayers. In addition, the amphiphile aggregation behavior at an air-water interface was studied by surface tension measurement, and lyotropic phase behavior …