Shear melting of a colloidal glass
[Under construction -- Nick Schade (fall 2009)]
The authors use confocal microscopy to investigate shear melting of colloidal glasses at the microscopic level. A phase transition occurs at a strain of about 8%, as this is when shear melting begins. For larger shear strain than this, cooperative motions of groups of particles can be found, where the average group size is about 3 particles. It is also evident that diffusive behavior of the particles is driven by shear for large strains. In particular, it is found that the effective diffusion coefficient is linearly proportional to shear rate, and this can be explained mathematically with a modified form of the Stokes-Einstein model of diffusion in which thermal energy is replaced by shear energy.
Authors: Christoph Eisenmann, Chanjoong Kim, Johan Mattsson, and David Weitz.
Date: February 4, 2009.
Departments of Physics and HSEAS, Harvard University, Cambridge, Massachusetts 02138, USA
Preprint (2009).