Ultra thin films of oligoimide through molecular assembly

Ultra thin oligoimide films are prepared through molecular assembly of monomers. Pyromellitic dianhydride (PMDA) and diaminodiphenylether (DDE) are assembled sequentially from their solutions on to Si substrates surface-modified with p-aminophenyltrimethoxysilane (APhS). X-ray photoelectron spectroscopy analysis shows that the PMDA/DDE interfacial reaction is complete. UV absorption confirms a linear growth of the film with the number of deposition steps. Atomic force microscopy exhibits a good morphological uniformity in the film with a surface roughness of less than 0.5 nm at each deposition.