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Chiroptical filters from aqueous (hydroxypropyl) cellulose liquid crystals
Author(s) -
Charlet Gérard,
Gray Derek
Publication year - 1989
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1989.070370905
Subject(s) - liquid crystal , mesophase , materials science , polarizer , hydroxypropyl cellulose , aqueous solution , optics , cellulose , cholesteric liquid crystal , bacterial cellulose , optoelectronics , composite material , polymer , organic chemistry , chemistry , birefringence , physics
An experimental procedure has been designed for the preparation of aqueous mesophases of (hydroxypropyl)cellulose (HPC) exhibiting a stable low turbidity Sandwich chiroptical filters have been made from these right‐handed cholesteric liquid crystals confined between two parallel glass plates. Their optical properties, studied with new circular polarizers prepared from oriented polyethylene films, depend on the mesophase thickness. Thin filters (liquid crystal thickness ≤ 200 μm) reflect selectively up to 36% of normal incident light (i.e., 72% of the right‐handed circularly polarized component) in a very narrow wavelength band (bandwidth ≤ 10 nm). An increase of the reflected intensity is observed at higher sample thickness, although it is accompanied by an increasing loss of selectivity of the filter toward circularly polarized light. However, a range of thickness exists where both selectivity and reflectivity are close to their optimum values. The availability, low cost, and UV resistance of (hydroxypropyl)cellulose make HPC–water liquid crystals attractive for optical applications.