Studies on photochemical isomerization of azobenzene in self-assembled bolaamphiphile monolayers

Photochemical reaction of azobenzene is investigated in systems in which sy mmetrically substituted chromophores are organized in self-assembled monomo lecular film of cationic bolaamphiphiles on fused silica. The bolaamphiphil es consist of an azobenzene chromorphore, attached symmetrically to an alky l chain on both sides; chain lengths, n, range from 6 to 16 carbons. We hav e studied the effects of chain length of the bolaamphiphile on an aggregate state in solution and in film, on trans-cis or cis-trans photoisomerizatio n kinetics, and on the degree of dichroism induced upon linearly polarized light irradiation. Our study suggests that the degree of dichroism and the photoisomerization in the self-assembled monomolecular film was strongly de pendent on the chain length.