Mechanical properties of a model of attractive colloidal solutions - art. no. 031501

We review the nature of glass transitions and the glasses arising from a sq uare-well potential with a narrow and deep well. Our discussion is based on the mode coupling theory (MCT), and the predictions of glasses that we mak e refer to the "ideal" glasses predicted by this theory. We believe that th e square-well system well represents colloidal particles with attractive in teractions produced by grafted polymers, or depletion interactions. It has been recently shown that two types of glasses, an attractive and a repulsiv e one, are predicted by MCT for this model. The former can form at quite lo w densities. Most of our attention is directed at the mechanical properties of the glasses predicted by this theory. In particular we calculate the el astic shear modulus at zero frequency and the longitudinal stress modulus i n the long wavelength limit. Results for both are presented along the glass -liquid transition curves and their interesting behavior is explained in te rms of the underlying physics of the system.