%0 Journal Article
%T Phonon Dispersion and Elastic Moduli of Two-Dimensional Disordered Colloidal Packings of Soft Particles with Frictional Interactions
%A Tim Still
%A Carl P. Goodrich
%A Ke Chen
%A Peter J. Yunker
%A Samuel Schoenholz
%A Andrea J. Liu
%A A. G. Yodh
%J Physics
%D 2013
%I arXiv
%R 10.1103/PhysRevE.89.012301
%X Particle tracking and displacement covariance matrix techniques are employed to investigate the phonon dispersion relations of two-dimensional colloidal glasses composed of soft, thermoresponsive microgel particles whose temperature-sensitive size permits \textit{in situ} variation of particle packing fraction. Bulk, $B$, and shear, $G$, moduli of the colloidal glasses are extracted from the dispersion relations as a function of packing fraction, and variation of the ratio $G/B$ with packing fraction is found to agree quantitatively with predictions for jammed packings of frictional soft particles. In addition, $G$ and $B$ individually agree with numerical predictions for frictional particles. This remarkable level of agreement enabled us to extract an energy scale for the inter-particle interaction from the individual elastic constants and to derive an approximate estimate for the inter-particle friction coefficient.
%U http://arxiv.org/abs/1306.3188v2