Synthesis of ultra‐thin films of aromatic polymers at air/water interface

Ultra‐thin films of and precursor polymers for polybenzimidazole (PBI), polybenzoxazole (PBO), or polybenzothiazole (PBT) were formed at air/water interface by spreading monomers and then polymerizing on the water surface. These thin films could be deposited onto appropriate substrates by using the LB method of horizontal lifting. Moreover, the heat‐treatment of the built‐up films of the precursor polymers of PBI, PBO, and PBT formed the ultra‐thin films of high temperature polymers. The resulting ultra‐thin films had uniform and controllable thickness, but remained fairly stable when subjected to temperature up to 300°C. They also had good solvent resistance.