Characterization of Polyacrylamide Gels by Dynamic Light Scattering Under the Microscope

Abstract

Tanaka, Hocker and Benedek¹ were the first to study dynamic light scattering from gels. Since then several investigations on acrylamide gels utilizing the photon correlation technique were reported.^2–6 Tanaka et al.² discovered the existence of a gel spinodal temperature at which the intensity of light scattered by the gel diverges. Hecht et al.⁴ found for their gel samples that the elastic modulus, measured from the intensity of quasi-elastically scattered light is in acceptable agreement with the scaling prediction for a good solvent. On the other hand, Gelman et al.⁶ found that for their gel preparations (water as solvent in both investigations) the rigidity data follow the scaling law for poor solvents. This indicates that the reaction parameters have an important role on the final structure of the gel preparations.