Biomedical subjects

A B Nych

Publications and source records attributed to A B Nych.

4 recordsLinked to original sources

PubMed2004

Ordered droplet structures at the liquid crystal surface and elastic-capillary colloidal interactions.

We demonstrate a variety of ordered patterns, including hexagonal structures and chains, formed by colloidal particles (droplets) at the free surface of a nematic liquid crystal (LC). The surface placement introduces a new type of particle interaction as compared to particles entirely in the LC bulk. Namely, director deformations caused by the particles lead to distortions of the interface and thus to capillary attraction. The elastic-capillary coupling is strong enough to remain relevant even at the micron-scale when its buoyancy-capillary counterpart becomes irrelevant.

Adsorption↗

PubMed2001

Crystal structure in nematic emulsion.

We describe the experimental observation of a crystal structure formed by glycerol droplets suspended in a nematic liquid crystal. The structure exhibits a high density hexagonal ordering. We have experimentally observed a noticeable interaction between droplets with tangential boundary conditions. Within the scope of known models we discuss the nature of appropriate mechanisms of the interaction.

Journal Article↗

PubMed2001

Deformation of liquid crystal droplets under the action of an external ac electric field.

Deformation of liquid crystal droplets suspended in liquid polymer matrix under the action of external electric field was observed in dependence of ion concentration in such system. Experimental dependence of droplet elongation vs electric field demonstrates nonmonotonous character with increase of ion concentration. The theory that provides the basic agreement with experimental observation is developed.

Journal Article↗

PubMed1999

Non-Debye screening of a surface charge and a bulk-ion-controlled anchoring transition in a nematic liquid crystal.

We study the anchoring mechanism due to substrate-adsorbed ions by examining a related anchoring transition. An analytical solution to the Poisson equation shows that, as their number suffices for a non-negligible anchoring contribution, the surface field is screened over some characteristic microscopic distance. It is shown both theoretically and experimentally that the critical temperature of the transition can be controlled by bulk ion density through its relation to the density of adsorbed ions.

Journal Article↗