Self-assembly films of tetrakis(hydroxyphenyl) porphyrins

The self-assembly of hydroxyphenyl substituted porphyrins on silicon wafer and mica has been studied with atomic force microscope (AFM). It was found that the shape of the aggregates formed by the porphyrin derivates is affected by both the molecular structures and substrate. Tetrakis(p-hydroxyphenyl) porphyrins form disk-like morphology on the mica and the silicon wafer. Tetrakis(m-hydroxyphenyl) porphyrins form porphyrin rings on the silicon wafer through the self-assembly, while form disorganized morphology on the surface of mica. The shapes of the aggregates formed by tetrakis(o-hydroxyphenyl) porphyrins on the mica are unstable and vary with the assembly condition, while it is a random network on the silicon wafer. The mechanism for the shape formation of the hydroxyphenyl-substituted porphyrins during the self-assembly process is discussed.