Polyhedral oligomeric silsesquioxanes: a new class of amphiphiles at the air/water interface.

Insoluble films of trisilanolisobutyl-POSS and octaisobutyl-POSS at the air/water interface are investigated by means of surface pressure - area per molecule isotherm (Pi - A) and Brewster angle microscopy (BAM). Analysis of the experimental results shows the partial cage molecule, trisilanolisobutyl-POSS, is a surface-active molecule that self-assembles into uniform monolayer upon compression; but the fully condensed cage molecule, octaisobutyl-POSS, is nonamphiphilic.