Dynamics of critical concentration fluctuations in gels

Abstract

The dynamics of concentration fluctuations in a gel near phase separation is described by a mode-coupling theory. The scaling relations, $E\propto \frac{1}{{\xi }^2}$ and $f\propto \frac{1}{\xi }$, where $\xi$ is the correlation length of the concentration fluctuations in the network, are obtained for the elastic constant of the network, $E$, and the frictional coefficient between the network and the fluid medium, $f$. The theory fully explains the experimental results of Tanaka, Ishiwata, and Ishimoto on a polyacrylamide gel.