Properties Of Polymer Dispersed Liquid Crystal Research Articles

Amplified stain-rate dependence of deformation in polymer-dispersed liquid-crystal materials

The mechanical properties of polymer-dispersed liquid crystals (PDLCs) are investigated to elucidate their fundamental microstructural and mechanistic underpinnings, and overall structural integrity under deformation. High strain-rate loading experiments and quasistatic compression tests on PDLC materials reveal an amplified strain-rate dependence relative to the matrix material. A finite-element micromechanical model of PDLC materials explains this behavior in terms of strain-rate concentrations at the equators of the spherical liquid-crystal droplets. The model also predicts a weak dependence of the aspect ratio of deforming liquid-crystal droplets on their volume fraction.

Stability Studies on Polymer Dispersed Liquid Crystal Films

Polymer Dispersed Liquid Crystal(PDLC) is a class of electroscattering materials exhibiting very promising properties for display device applications. For the last few years, the electrooptical properties of PDLC have improved drastically to use projection device with high brightness. We have studied stability of PDLC films which formed by ultraviolet initiated photopolymerization and liquid crystal phase separation. We evaluated several stability items in PDLC films such as running and environment test, accelerated life time at low and elevated temperature, voltage holding ratio(VHR) variations according to UV exposing time and temperature.

A Calorimetric Determination of Fundamental Properties of Polymer-Dispersed Liquid Crystals

Abstract We have developed a combined calorimetric/electron microscopic technique for determining several fundamental properties of polymer-dispersed liquid crystal (PDLC) films. Calorimetry allows us to determine the solubility limit of liquid crystal in the polymer matrix as well as the fraction of liquid crystal which is dispersed in the form of microdroplets. By combining the calorimetry results with electron microscopy measurements of D, the microdroplet diameter, we are able to calculate the functional relationship between the droplet number density and D. All of these parameters are of considerable importance in assessing the behavior of PDLCs. The usefulness of the method is illustrated by applying it to thermally-cured epoxy-based systems.