Planar degenerated anchoring of liquid crystals obtained by surface memory passivation

Abstract

Weak anchoring of liquid crystals on solid substrates is usually dominated by the surface memory. We show that the memory can be removed by surface passivation by silane molecules. We realize planar, azimuthally degenerated, and memory-free anchorings without pretilt.

Lehmann effect in a compensated cholesteric liquid crystal: Experimental evidence with fixed and gliding boundary conditions

“…On the other hand, this does not exclude a viscous friction at the surface. The first gliding anchoring was found by Dozov et al [24] and consists of treating the glass plates with a thin layer of (3-glycidoxypropyl) trimethoxysilane (3-GPS). The second one, better according to Blanc et al [25], consists of covering the glass with the commercial photopolymer NOA 60 (provided by Norland Optics) which is then polymerized by exposure to UV light.…”

“…In order to model the central anchoring defect, we assume that its main effect is to locally increase the liquid crystal viscosity. Under this assumption, viscosity γ 1 in equation (24) becomes a function of r of the type:…”

Nematic Bistable Device Using a Metastable Anti-Conical Surface Anchoring

“…However, several kinds of degenerated alignments were reported on memoryfree polymer surfaces. In the planar degenerated case [9] the easy directions form an "easy plane", defined by θ s = π /2 . For the conical anchoring [10] the energy minima are along an "easy cone", defined by θ s = θ c <π /2.…”

Structural consideration of the additive effects on the electro-optical properties of commercial nematic liquid crystal materials

“…However, due to the high surface anchoring energy of the LC at the alignment layer, the response times and viewing angles are limited. Therefore, various methods were investigated in order to lower the anchoring energy, for example soft rubbing [2], photo-induced alignment [3], obliquely evaporated alignment layer [4], interface treatments between the LC and alignment layer [5][6][7][8][9][10], etc. Although such treatments provide a means of weak anchoring, the conditions in which these can be applied are restricted.…”