Colloidal aggregation and dynamics in anisotropic fluids

• DOI: 10.1073/pnas.1321903111
• Publication Date: 2014-04-09T06:59:49Z
• Authors: Frédéric Mondiot; Robert Botet; Patrick Snabre; Olivier Mondain-M...; Jean-Christophe L...
• Keywords: elasticity; colloidal dispersion; liquid crystal; 02 engineering and technology; 0210 nano-technology; [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]; [PHYS.COND.CM-SCM] Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]

SignificanceThe formulation of colloidal particle/liquid crystal (LC) composites is a well-identified route toward the design of smart responsive materials with tunable optical or mechanical properties. However, the particles aggregate because they distort the intrinsic order of LC phases, which costs elastic energy. For micrometer-sized inclusions, the resulting elastic forces dominate the coarsening of the system. In this paper, we find a previously unidentified regime where elastic interactions no longer prevail when the particles are downsized to the nanometer scale. Instead, the system evolution is governed by an anisotropic Brownian diffusion coupled to attractive depletion interactions. This finding opens up new possibilities to better control the clustering of colloids in such media. We provide both experimental evidence and numerical simulations.