Gelation of diluted colloidal systems

M. E. BRITO; M. A. CARIGNANO; V. I. MARCONI

Villa Carlos Paz

Workshop; XIII Latin American Workshop on Nonlinear Physics - LAWNP 2013; 2013

Dipolar colloidal systems, one of the simpler materials presenting anisotropic interactions, have attracted recent attention since their interactions are easy to control and represent a building block for the design of new soft materials. Using stochastic dynamics simulations we investigate the gelation process in a high dilute system of dipolar colloidal particles with implicit solvent. This system self assembles in a rich variety of structures, where we highlight three different regimes at very low packing fraction and decreasing temperature: fluid, string- fluid and string-gel. We perform simulations assuming a continuous model for the solvent in which the particles are embedded, and explicit particle-particle interactions. We present a phase diagram, density vs temperature, determined from thermodynamics and structural analysis. We characterize as well in detail the string-gel structure studying the topological defects as a function of the packing fraction, and the porosity versus both, temperature and dielectric constant. In addition we study the particular system slow dynamic behavior at very low temperature.