Fast transient fluorescence technique for monitoring swelling of poly(methyl methacrylate) gels

Abstract

A fast transient fluorescence technique (FTRF) which uses the Strobe Master System (SMS), is introduced for studying swelling of a cylindrical poly(methyl methacrylate) (PMMA) gel. PMMA gel was prepared by free radical copolymerization of methyl (methacrylate) (MMA) and ethylene glycol dimethacrylate (EGDM). Pyrene (Py) was introduced as a fluorescence probe during polymerization and lifetimes of Py were measured during in situ swelling process. Chloroform was used as a swelling agent. An equation is derived for low quenching efficiencies to interpret the behavior of mean lifetimes 〈τ〉 during swelling. It was observed that 〈τ〉 values decreased as swelling proceeded. The Li–Tanaka equation was used to determine the cooperative, Dc and mutual Dm diffusion coefficients, which were found to be around 10−5 and 10−7cm2ns−1, respectively.