Using Depolarized Dynamic Light Scattering to Characterize Microgel Dependence on Synthesis Temperature

Microgels formed by crosslinking polysaccharide polymer chains exhibit a thermally reversible volume phase transition due to the amphiphilic properties of the parent polymer. Specifically, the microgels deswell above a volume phase transition temperature, T_v. Microgel dynamics above and below T_v has been studied extensively by dynamic light scattering (DLS) before. Here, the structure and dynamics of microgels synthesized at various temperatures are investigated through the use of depolarized dynamic light scattering (DDLS). The technique has previously been used in our lab to examine solely geometric anisotropies in non-spherical particles. It has also been used in the literature to study shape fluctuations in microgels that have a hard, polystyrene core and a soft, polymer shell. This research project looks into a possibility that the observed DDLS signal above T_v, for microgels synthesized at various temperatures, arises from microgel shape fluctuations.