Abstract
The absorption of radiation by polymeric systems containing aromatic units produces photo-excited states. This phenomenon has generated considerable research interest since polymeric systems may be used for energy collection and transmission. Ultra-violet
absorption by fluorophores attached to a polymer chain and the subsequent energy migration by a way of exitations are subjects of theoretical interest. A series of copolymers of acenaphthalene (ACN) with acrylonitrile (AN), 2-vinylnaphthalene (2-VN), methylacrylonitrile (MAN), by emulsion polymerization, has been prepared. Fluorescence spectra showed both monomeric (350 nm) and excimeric (480 nm) peaks. Exciton migration lengths were calculated by quenching techniques using oxygen and Stern-Volmer relationship. L = (ksv / 2π Ro No )1/2. Chain rigidity in poly (ACN) hinders excimer formation except for the helix conformation. Introduction of flexible (AN), (MAN) and (2-VN) units along the chain allows excimer formation of different %ACN concentration. Copolymer containing 53.5% ACN had the longest migration distance (93Å). The energy migration lengths, as a percentage of the end-to end distance, were calculated. The relation between the energy migration (L) and the end-to end distance (r -2)1/2 has been compared for the three different copolymers