Orientational ordering of Janus colloids in cholesteric liquid crystals

Abstract

In this paper we show that Janus colloids, which are spherical particles with hybrid anchoring conditions, have preferable orientations in cholesteric media depending on the cholesteric wave vector. Simulations reveal that the tilt angle of a particle varies greatly with variation of the particle diameter to the cholesteric pitch ratio, which makes it possible to stabilize the appropriate particle orientation and to control it by variation of the cholesteric pitch.

Bipolar configuration with twisted loop defect in chiral nematic droplets under homeotropic surface anchoring

“…We used the extended Frank elastic continuum approach with Monte-Carlo annealing optimization 42 to find energy-optimal droplet structures. It previously shown good results for nematic and cholesteric LC 42 , 43 . This approach includes the effects of the director field distortion and the formation of defects in the droplet: where K 11 , K 22 and K 33 are the splay, twist and bend elasticity constants, respectively, W is the surface anchoring energy density, ϑ is the angle between local director n and surface normal of the droplet, and F def is the energy of defects calculated by the summation of the point and linear defect energies.…”