Electrically driven kinklike distorting waves in microsized liquid crystals.

Electrically driven kinklike distortion regimes in a microsized liquid crystal channel have been investigated both experimentally and analytically. Kinklike distortion waves were excited by the interaction between the electric field E and the gradient ∇n[over ̂] of the director field in a homogeneously aligned liquid crystal (HALC) channel. Having obtained the evolution of the normalized light intensity, which was recorded by the high-speed camera, the process of excitation and evolution of the traveling wave in the HALC channel was visualized for the first time.

Light-Triggered Manipulations of Droplets All in One: Reversible Wetting, Transport, Splitting, and Merging.

Here, we establish different ways of light-triggered droplet manipulation such as reversible wetting, splitting, merging, and transport. The unique features of our approach are that the changes in the wetting properties of microscopic droplets of isotropic (oil) or anisotropic (liquid crystalline) liquids adsorbed on photoswitchable films can be triggered just by application of soft optical stimuli, which lead to dynamical, reversible changes in the local morphology of the structured surfaces. The adaptive films consist of an azobenzene-containing surfactant ionically attached to oppositely charged polymer chains.

Electrically driven nematic flow in microfluidic capillary with radial temperature gradient.

An electrically driven fluid pumping principle and a mechanism of kinklike distortion of the director field n[over ̂] in the microsized nematic volume has been described. It is shown that the interactions, on the one hand, between the electric field E and the gradient of the director's field ∇n[over ̂], and, on the other hand, between the ∇n[over ̂] and the temperature gradient ∇T arising in a homogeneously aligned liquid crystal microfluidic channel, confined between two infinitely long horizontal coaxial cylinders, may excite the kinklike distortion wave spreading along normal to both cylindrical boundaries. Calculations show that the resemblance to the kinklike distortion wave depends on the value of radially applied electric field E and the curvature of these boundaries.

Electrically driven nematic flow in microfluidic devices containing a temperature gradient.

Fluid pumping principle has been developed utilizing the interaction, on the one hand, between the electric field E and the gradient ∇n[over ̂] of the director's field, and, on the other hand, between the ∇n[over ̂] and the temperature ∇T gradient arising in a homogeneously aligned liquid crystal (HALC) microfluidic channel. Calculations, based upon the nonlinear extension of the classical Ericksen-Leslie theory, with accounting the entropy balance equation, show that due to the coupling among the ∇T, ∇n,[over ̂] and E in the HALC microfluidic channel the horizontal flow v=v_{x}i[over ̂]=ui[over ̂] may be excited. The direction and magnitude of v is influenced both by the heat flux q across the microfluidic channel and the strength of the electric field E.

Liquid crystalline droplets in aqueous environments: electrostatic effects.

We demonstrate the strong impact of electrostatic properties on radial-bipolar structural transitions in nematic liquid crystal (LC) droplets dispersed in different aqueous environments. In the experimental part of the study, we systematically changed the electrostatic properties of both LC droplets and aqueous solutions. Mixtures of nematics were studied by combining LC materials with negative (azoxybenzene compounds) and strongly positive (cyanobiphenyl) dielectric anisotropy.