POLYMER LANGMUIR-BLODGETT-FILMS CONTAINING PHOTOFUNCTIONAL GROUPS .2. ELECTRON-TRANSFER QUENCHING IN POLYMER LANGMUIR-BLODGETT-FILMS CONTAINING CARBAZOLE CHROMOPHORE

N-Vinylcarbazole (Cz), being nonamphiphilic, has been introduced into Langmuir-Blodgett (LB) film as a comonomer of N-dodecylacrylamide (DDA) which has an excellent ability to form monolayer and LB multilayer. The spreading behaviors of the DDA/Cz copolymers with various Cz contents on a water surface were investigated by a measurement of the surface pressure-surface area isotherms. The isotherms show that the DDA/Cz copolymers even with 30% Cz mole fraction form a stable condensed monolayer on pure water and the carbazole chromophore is dispersed uniformly having its own surface area on the water surface. The copolymer monolayer could be transferred onto solid supports successively by the Langmuir-Blodgett method (Y-type deposition). The electron transfer from the excited carbazole chromophore in the copolymer monolayer to a viologen acceptor incorporated in the adjacent monolayer has been studied in LB film assembly by using an emission quenching method. Very effective quenching occurred due to the energy migration between the carbazole chromophores. It was found that the electron transfer quenching efficiency was varied by the mole fraction of carbazole content, which is related to the density of excimer site, and the quenching was determined by the result of the competition of energy migration to the carbazole facing the viologen quencher and to the energy-trapping site (an excimer formation site).