NEW OPTICAL MEMORY EFFECTS IN POLYMER-STABILIZED CHOLESTERIC LIQUID CRYSTALS DUE TO PITCH CHANGES DURING THE UV-CURING

摘要

A Polymer-Stabilized Cholesteric Liquid Crystal (PSCLC) is elaborated by combining the UV-curing with a thermally-induced pitch variation. We intend investigating possible memory effects into the characteristics of the reflection band of the PSCLC when the material comes back to the room temperature. Different thermal processes are studied when the curing occurs at one or two temperatures (with the role of the inverse sequence for the latter case). In the visible spectrum, the reflection bandwidth can be tuned in agreement with the chosen process and broadened by several orders of magnitude. The PSCLCs are switchable: broadened reflective, scattering and transparent states are the main modes occurring when a cell is subjected to an increasing voltage. Related application fields are smart windows for the control of solar light spectrum and white-or-black polarizer-free reflective displays.