The vibrational motions of particle gels

A simple discussion of the nature of repulsive and attractive glasses is given, and results presented in the framework of idealized mode coupling theory (MCT). The attractive glass is considered to be equivalent to the particle gel state observed in colloidal science, and the repulsive glass is equivalent to the dense colloidal glass that has recently been studied in colloidal science. Given the equivalence between a particle gel and a glass, it is possible to use MCT to calculate the dynamical structure factor, and thereby the spectrum of all vibrational motions in the glass. We present such spectra for a more and less dense particle gel state, and interpret the motions predicted by the theory. It is pointed out that such motions should resolve between what we call the particle gel, and the traditional repulsive colloidal glass, and as such are perhaps a most promising manner in which to study particle gels in the future.