Characterization of the reversible interaction of pairs of nanoparticles dispersed in nematic liquid crystals.

Observations of reversible interactions between pairs of chemically functionalized nanoparticles dispersed in nematic liquid crystals (LCs) are reported. In contrast to the irreversible association of microparticles in nematic LCs, by using gold nanoparticles and darkfield microscopy, particle tracking reveals the pairwise interactions of the nanoparticles in nematic LCs to be long-ranged and reversible. The measured range and strength of the pairwise interaction of the nanoparticles in the LCs was found to differ substantially from past theoretical predictions of nanoparticle interactions in LCs. The observation of reversible interactions between nanoparticles in LCs suggests that nematic LCs may provide new routes to spontaneous formation of ordered nanoparticle arrays.