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Self-diffusion coefficient studies in polystyrene/polystyrene/ toluene solutions: Dynamic light scattering and fluorescence recovery after photobleaching experiments

Research paper by L. Meistermann, M. Duval, B. Tinland

Indexed on: 01 Jul '97Published on: 01 Jul '97Published in: Polymer Bulletin



Abstract

The dynamical behavior of a polystyrene(Mw1)/polystyrene(Mw2)/toluene ternary mixture has been investigated by Dynamic Light Scattering (DLS) and Fluorescence Recovery After Photobleaching (FRAP). The experiments were made at several total polymer concentrations CT from dilute to semi-dilute range of concentration. In FRAP experiments, the dynamic of such a system is characterized by the existence of one relaxation mode identified to the self-diffusion coefficient Ds of the labelled polymer. This mode has been compared to the corresponding extracted Ds value from the two relaxation modes observed in DLS. The comparison between the results shows that in the semi-dilute range of concentration the agreement is good between both Ds values. As the concentration decreases, the agreement becomes less and less satisfactory, showing the limitation of the theory used to extract Ds from DLS measurements to the semi-dilute regime.