Polymer Diffusion in Gel-Containing Poly(vinyl acetate-co-dibutyl maleate) Latex Films

Abstract

Polymer interdiffusion in a poly(vinyl acetate-co-dibutyl maleate) [poly(VAc-co-DBM)] latex film containing ca. 50 wt % gel was studied by Forster resonance energy transfer (FRET). The latex particles were labeled either with an energy donor dye or with an acceptor dye. Films prepared from a mixture of donor- and acceptor-labeled particles exhibit nonexponential donor fluorescence decay profiles, which were analyzed in two distinct ways. In a first simplified approach, we calculated the fractional growth in the quantum efficiency of energy transfer fm, from which we obtained an apparent diffusion coefficient, Dapp, which decreases with increasing annealing time. In addition, we developed a new model for spherical diffusion that accounts for the presence of immobile gel nanodomains within the latex particles. We calculate the energy transfer from the donors in one particle to the acceptors in another, taking into account the concentration profile of the polymer arising from diffusion of the un-cross-linked...