Simulations of Topological Defects in Nematic Liquid Crystal Films

Abstract

We present a detailed computer simulation study of the formation and evolution of topological defects in thin 3D nematic films with schlieren geometry. The differences between the uniaxial and the biaxial case and the influence of the strength of anchoring to the surfaces are analyzed.

Some reflections on defects in liquid crystals: from Amerio to Zannoni and beyond

“…[70]), and the existence of knotted disclinations acting a kind of glue holding colloidal particles together in this context. Unfortunately, we cannot do justice to recent progress, save to observe that the Bologna group has been very active [71][72][73][74][75]. As a final postscript, given the renewed interest in biaxial liquid crystals [76] we mention very recent work from the Bologna group on the structure of droplets of nematics which consist of molecularly biaxial particles [77] .…”

Computer simulations of the ordering in a hybrid cylindrical film of nematic liquid crystals

“…To qualitavely appreciate the differences between the two cases studied here, we have also simulated the polarizing microscopy textures which have proved useful to investigate other confined nematic systems such as droplets [13][14][15], planar films, and twisted nematic display cell [16][17][18]. The textures were simulated by means of a Muller matrix approach [24], assuming, as usual, that the molecular domains represented by the spins act as optical retarders on the light propagating through the sample [25].…”

“…Here we have started to combine the simulation and continuum theory approaches to investigate the problem of nematics confined between concentric cylindrical surfaces [11,12]. Even though the model, described in the next section, is very simple, we have shown that it is sufficient to describe adequately systems where experimental results are available, as it proved possible for spherical PDLC droplets [13][14][15] and thin films [16][17][18]. The aim of this work is to study the effect on molecular organization of antagonist boundaries on the two cylindrical surfaces and of exchanging the inside and outside anchoring conditions.…”