Fluorescence Excitation Spectroscopy of Polystyrene Near the Critical Concentration c*
Journal of Applied Polymer Science, 104, 360- 364, February 2007
James E. Hanson, Ph.D. Department of Chemistry and Biochemistry
The critical concentration c* was measured using both fluorescence excitation spectroscopy and light scattering for four narrow molecular weight distribution samples of polystyrene (MW ¼ 225,000–1,500,000) in bicyclo[4.4.0]decane (decahydronaphthalene, decalin) at 20 and 308C. A discontinuity in the corrected intensity of a band in the excitation spectrum (assigned to the dimmer complex) as a function of concentration allowed determination of the critical concentration, c*, from the excitation spectra. The c* resulting from fluorescence and light scattering were identical within experimental error and were comparable to c* values calculated from literature methods. Fluorescence excitation spectroscopy should be a convenient method for determiningc* for aromatic polymers.