Fluorescence studies of polystyrene in different solvents

This investigation was done to have a systematic study of the Fluorescence of Polystyrene polymer with respect to concentration and solvent. A wide range of concentration was selected for Fluorescence studies and four different solvents i.e 1,2- Dichloroethane, Cyclopentane, n-Butylacetate and Cyclohexane were employed for this work. The Fluorescence peak at 335 nm was selected to be due to excimer emission while the peak at 283 (or 286) nm was selected to be due to monomer emission, and the exciMCT and monomer intensities were measured at these wavelengths for all the solvents under investigation. The R values (i.e. I-E/I-M ratio) were found for all the solutions and were found to increase with concentration. This increase is thought to be due to several effects including intermolecular excimer formation, remote adjacent intramolecular excimer formation, coil contraction and so on. The R values remarkably depend upon nature of the solvent. The Fluorescence emission intensity ratio (I-E/I-M) is in the order of n-Butylacetate < 1,2-Dichloroethane < Cyclohexane < Cyclopentane. R is shown to be higher in poor solvent while it is low in good solvent.