Interactions of single nanoparticles in nematic liquid crystal

M. Škarabot, A. V. Ryzhkova, I. Muševič

We studied interactions of single silica nanoparticles with homeotropic surface anchoring in a confined planar nematic liquid crystal cell. Nanoparticles form stable pairs down to a size of 35 nm with the pair binding energy proportional to the size of the particle. 22 nm particles do not form stable pairs, only metastable states were observed due to strong thermal motion and electrostatic repulsion. These nanoparticles strongly interact with the confining surfaces and the larger clusters, which prevents the formation of stable homogenous dispersions. In addition we have shown that nanoparticles are strongly attracted by topological defects induced by the microparticles. The origin of the attractive forces in nanoparticle dispersions is the minimization of free energy. These forces strongly depend on the strength and type of the liquid crystal anchoring at the surface of the nanoparticles.

DOI