A Photoluminescent LB Film of a Polyurethane with Cyanostilbene Side Group

Abstract

The dependence of photoluminescent property on the molecular orientation in polymeric thin films was investigated using spin-coated and LB films. A polyurethane (PU-CN) was prepared from condensation polymerization of a cyanostilbene diol and 2,4-toluene diisocyanate. The PU-CN monolayer was characterized by surface pressure-area isotherms and Brewster angle microscopy. Additional UV-Vis absorption peak was observed at 350 nm in the LB film. A blue shift was found in the PL emission of the LB film when compared with that of the spin-coated film. The cyanostilbene side groups were supposed to stack partly together as J-aggregate in the LB film.