Modeling of Swelling by the Fast Transient Fluorescence Technique in a Polymeric Gel

摘要

The time-resolved, fast transient fluorescence technique, whcih uses a strobe master system, was employed for studying the swlling of a disc-shaped poly-(methyl methacrylate) gel. The disc-shaped gel was prepared by free-radical copolymerization of methyl methacrylate and ethylene glycol dimethacrylate. Pyrene(Py) was introduced as a fluorescence probe during polymerization. After this gel was dried, swelling and slow-release experiments were performed in chloroform at room temperature. Lifetimes of Py were measured during in situ swelling and slow-release experiments. An aquation was derived for low-quenching efficiencies to interpret the behavior of lifetimes in and out of the gel during swelling. Py lifetimes in the gel decreased as swelling proceeded, but Py lifetimes out of the gel stayed constant during the slow release experiments. The Li-Tanaka equation was used to determine the cooperative and mutual diffusion coefficients, whcih were around 10~(-5) and 10~(-7) cm~2s~(-1), respectively.