Swelling of heterogels in good solvents; a fast transient fluorescence study

The swelling of disc-shaped heterogels were studied using Fast Transient Fluorescence Technique (FTRF). Disc-shaped heterogels were prepared by combination of methyl-methacrylate (MMA) and styrene (S) with ethylene glycol dimethacrylate (EGDM) as a crosslinker agent in the presence of 2,2′-azobisisobutyronitrile (AIBN). Pyrene (Py) was introduced as an extrinsic floroprobe during polymerisation. Lifetimes of Py were measured during in situ swelling processes of heterogels in good solvents to determine the relation between the diffusion and solvent quality. An equation is derived for low-quenching efficiencies to interpret the behavior of lifetime of Py during swelling. Li–Tanaka equation was employed to determine the cooperative diffusion coefficients, Dc in heterogels, which were found to be strongly correlated with the chosen solvent and the polymeric material in the heterogel system.