Thermal stability of amphiphilic di-block copolymer monolayer

Monolayers of amphiphilic di-block copolymer, PEO40-b-PMA(Az)(19) on water surface and solid surfaces, such as silicon wafer and quartz glass, were analyzed by surface pressure - molecular area (pi-A) isotherm, UV-Vis spectroscopy, atomic force microscopy (AFM) and total X-ray reflectivity (TXR). The monolayer prepared at 22 mN m-1 consisted of H aggregated azobezene (Az) moieties, which orientated perpendicular to the solid surface. The monolayer structure, including H aggregated Az and orientation of Az, was stable after annealing at 98 degrees C, at which temperature the hydrophilic PEO domain was the liquid phase and the hydrophobic PMA(Az) was in the smectic A phase.