STRUCTURES AND PHOTOISOMERIZATION OF THE POLYION COMPLEX LANGMUIR-BLODGETT-FILMS OF AN AMPHIPHILE BEARING 2 AZOBENZENE UNITS

The structures and the photoisomerization of polyion complex Langmuir- Blodgett (LB) films of an amphiphile bearing two azobenzene units were studied, The anionic amphiphile was spread on the aqueous subphases w ith and without polycations. The area per molecule depended on the pol ycation species and was larger than that of pure amphiphile for three polycations out of four, It was suggested that the area per molecule i s determined by the compromise between the various intermolecular inte ractions involved in the formation of the monolayer, The LB transfer w as possible for all the polyion complex systems and reversible photois omerization was observed for all the LB films by alternate UV and visi ble light irradiation, As the area per molecule where the LB transfer was conducted increased, the fraction of the cis isomer at the photost ationary state with UV light irradiation increased, suggesting the rol e of free volume in the trans-to-cis photoisomerization.