Hydrogen bonding versus van der Waals interactions: competitive influence of noncovalent interactions on 2D self-assembly at the liquid-solid interface.

The structures of the self-assembled monolayers of various 4-alkoxybenzoic acids physisorbed at the liquid-solid interface were established by employing scanning tunnelling microscopy (STM). This study has been essentially undertaken to explore the competitive influence of van der Waals and hydrogen-bonding interactions on the process of two-dimensional self-assembly. These acid derivatives form hydrogen-bonded dimers as expected; however, the dimers organise themselves in the form of relatively complex lamellae.

Role of pseudopolymorphism on concentration dependent competitive adsorption at a liquid/solid interface.

We present for the first time a peculiar concentration effect on competitive adsorption of a binary mixture at the liquid/solid interface, which we attribute to the existence of pseudopolymorphism and its concentration dependence. These results are helpful for the understanding of phase behavior of multi-component systems at the interface.