Driving the assembly of anisotropic nanoparticles using liquid crystalline solvents: Insights from computational modeling

ANYL 174

Francisco R. Hung, frhung@lsu.edu, Cain Department of Chemical Engineering, Louisiana State University, 110 Jesse Coates Hall, S. Stadium Rd., Baton Rouge, LA 70803
In this work we use computer simulation to investigate systems of nanoparticles in nematic liquid crystals (NLCs). We aim at understanding the behavior of these nanoscale systems, in order to explore potential applications in photonics, optical sensors and electro-optical nanoswitches, and complement experimental efforts. Previous work has focused on spherical and rod-like particles in NLCs. The particles' inclusion distorts the NLC, giving rise to strong interparticle interactions that can induce the formation of ordered structures. Such interactions are reversible and disappear when the nematic is driven into the isotropic phase.

We report results for the potentials of mean force and the defect structures that arise when nanoparticles are immersed in a NLC. Using a mesoscale theory in terms of the tensor order parameter Q of the NLC, we have analyzed several systems of nanoparticles with different shapes (e.g., spherical, spherocylindrical, faceted polyhedra) and/or functional groups patterned at their surfaces. The NLC forms peculiar defect structures around these nanoparticles, which adopt preferred orientations relative to the director field n(r). As a result, strong anisotropic interparticle interactions arise between the nanoparticles, which could be used to drive them to assemble into unique structures.