Lubricity of cholesteric liquid-crystal nanomaterials in friction of solids

Abstract

A physical model of the lubricity of cholesteric liquid-crystal nanomaterials has been proposed in accordance with which the transition from single-crystal layers of a cholesteric liquid-crystal nanomaterial to polymolecular structurally sensitive liquid-crystal films, which occurs with varying temperature and is governed by the effect of molecules of cholesteric liquid-crystal compounds contained in the lubricant, as well as the reverse transition, lead to a reversible change in the shear resistance. This change results from the formation of continuous planar-oriented and helically twisted boundary layers in the zone of dynamic contact, which consist of molecules of the cholesteric liquid-crystal nanomaterials. The pitch distance of the helix and, therefore, the thickness of cholesteric liquid-crystal films of these nanomaterials exhibit a structurally sensitive response to changes in the temperature in the friction zone, which varies the dissipation of the energy during friction.