FORSTER ENERGY-TRANSFER BETWEEN LANGMUIR-BLODGETT-FILM LAYERS IN AQUEOUS-SOLUTION

The Forster energy transfer between chromophores in several different types of Langmuir-Blodgett (LB) films exposed to aqueous conditions wa s examined. The donor and acceptor chromophores were either contained in a monolayer of a preformed copolymer incorporating amphiphilic side chains and hydrophilic spacer groups (dansyldihexa-decylamine as the donor and -dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlora te as the acceptor) or grafted to a monolayer of such a copolymer (ant hracene as the donor and 7-nitrobenz-2-oxa-1,3-diazole as the acceptor ). The monolayers containing donor or acceptor chromophores were separ ated by neutral spacer layers of cadmium arachidate or copolymer mater ial. It was found that the unattached chromophores diffused through th e LB films during the experimental procedure and for several days afte rwards. LB films containing chromophores that were grafted to copolyme r and copolymer material spacer layers possessed high translayer struc tural order. There was evidence, however, that indicated that the stru cture relaxed with time.