Light scattering of particles embedded in soft hydrogel

This study is concerned with soft polyacrylamide gels in which are embedded either polystyrene latexes or block copolymer micelles with polystyrene cores and poly(methacrylic acid) shells. We have found that light scattering provides useful structure information about the systems. For polystyrene latexes, both molar mass and radius of gyration do not change during the embedding in the hydrogel; for block copolymer micelles, molar mass does not change, while the size decreases upon immobilization. In all cases, the second virial coefficient is very small and overshadowed by the turbidity of the sample. For large particles with narrow particle size distribution, a combination of Guinier and Zimm plots has been used for obtaining the particle size and molar mass.