Characteristics of nanoparticle-doped homeotropic liquid crystal devices

Abstract

We have found that nanoparticles of polyhedral oligomeric silsesquioxane (POSS) can induce vertical alignment in nematic liquid crystal (LC) cells as long as the doped weight percentage of POSS in the LC cells is higher than ∼1%. Such nanoparticle-induced vertical alignment (NIVA) is a very suitable technique for application in the low-temperature fabrication of plastic LC displays. The dynamic process of LC orientation from randomly parallel alignment to vertical alignment was recorded, and it is posited that the POSS NIVA is due to the adsorption of POSS on the inner surfaces of the LC cells. The influence of the POSS concentration on the electro-optical properties and dielectric constant of LC cells was also investigated and the results indicate that LC cells doped with ∼1 wt% POSS provide the best electro-optical performance.

Controlling the Alignment of Polyimide for Liquid Crystal Devices

“…Recently, we have developed a new approach to align LC vertically by adding polyhedral oligomeric silsesquioxane (POSS) nanoparticles in LCDs (Jeng et al, 2007;Hwang et al, 2009). POSS nanoparticles with nano-sized cage structures have been incorporated into polymers for improving their thermal, mechanical and oxidation resistance (Xiao et al, 2003;Yei et al, 2004).…”

Polyhedral Oligomeric Silsesquioxane Films for Liquid Crystal Alignment

“…In recent years, nanoparticle-doped LCDs have been widely investigated in efforts to change the electro-optical properties [1]. Spontaneous homeotropic alignment of LCs was observed by adding polyhedral oligomeric silsesquioxane (POSS) nanomaterials in the LC layer [2,3]. The developed technique of POSS-induced homeotropic alignment has been shown to have many applications in LCDs, such as flexible LCDs [4], the pretilt angle control and stabilization of LCs [5,6] and dual LC alignment [7,8].…”

“…Instead of doping a specific type of POSS in the LC layer, as done in our previous works [2,3], POSS nanomaterials with various polar functional groups, employing different thermal treatments for producing POSS films, were applied as LC alignment films in this work. Our developed PI-less technique, applied to generate homeotropic alignment, is based on doping POSS nanomaterials in the LC layer [2,3].…”

Effects of Nanoscaled Tin-Doped Indium Oxide on Liquid Crystals against Electrostatic Discharge

“…So far the subjects have included various kinds of materials such as metallic Ag-or Pd-nanoparticles [1,2], CNTs [3,4,[11][12][13], diamond particles [14], semiconductive nanotubes [15], cage-like polymeric molecules such as polyhedral oligomeric silsesquioxanes (POSS) [16,17], and ferroelectric particles [5,18]. By using these nanoparticle candidates, newly found texture, switching behavior, or enhanced electro-optical response for the modified LC can be achieved.…”