The Influence of Temperature on the Characterization of Water-Soluble Polymers Using Asymmetric Flow Field-Flow-Fractionation Coupled to Multiangle Laser Light Scattering

Asymmetrical flow field-flow fractionation coupled to multiangle laser light scattering has been shown to be an effective method to determine the molar mass distribution of polysaccharides. Two polymer standards, dextran and pullulan, were analyzed in the temperature range 30-60 degrees at intervals of 10 degrees C. The weight average molar mass and molar mass distribution obtained at each temperature agreed well with quoted values. The diffusion coefficient, hydrodynamic radius, radius of gyration, and activation energy of diffusion were calculated and all agreed well with literature data obtained by dynamic and static light scattering. The asymmetry factor Rg/Rh suggests a flexible random coil conformation for both polymers, which was supported by the molar mass dependence of both the radius of gyration and the hydrodynamic radius. The results show the potential of asymmetric flow field fractionation coupled to multiangle laser light scattering in undertaking measurements of molar mass distribution as a function of temperature.