Fluorescence lifetime distributions: Applications to high and low viscosity media in polymer blend-like particles

Abstract

Abstract Fluorescence measurements were carried out in poly(vinyl acetate) (PVAc) particles which were prepared by dispersion polymerization in isooctane using a copolymer of 2-ethylhexyl methacrylate (PEHMA) as a steric stabilizer. These reactive particles were labelled by naphthalene (N) in the stabilizer phase. N fluorescence decay profiles were measured and apparent dimension of d app = 2.3 for the energy transfer process was explained in terms of geometrical crossover in a restricted geometry if the PEHMA is present in the form of interconnected, long wiggly threads. Swelling measurements were performed with cyclohexane as swelling agent and it was found that the energy transfer kinetics obeyed a Stern-Volmer type of relation in a highly swollen-nonrestricted environment in the PEHMA phase.