Energy transfer studies from polymer bound naphthalene to anthracene in solution: translational and segmental diffusion rates

A graft copolymer of polyisobutylene with poly(methyl methacrylate) [PMMA] was prepared containing naphthalene [N] groups statistically distributed along the PMMA backbone. Fluorescence studies of dilute solutions of the polymer in ethyl acetate showed small amounts of N-excimer emission when the NMA/MMA ratio was 1:9, and undetectable excimer when the ratio was 2 98 . Energy transfer experiments were carried out between polymer-bound naphthalene and anthracene [A] added to the solution. The rate constant for energy transfer, k ET, for the process N∗ + A → N + A∗ was found to be 1.1 × 10 10 M −1 s −1 at 22°, slightly smaller than that (1.2 × 10 10 M −1 s −1) for energy transfer from naphthylmethyl pivalate to A. From the value of the rate constants, a value for the segmental diffusion coefficient of polymer bound naphthalene was calculated.