Relation Between the Supermolecular Structure and Optical Properties of Liquid Crystal - Photopolymer Composite Films

• Published in: Molecular crystals and liquid crystals (Philadelphia, Pa. : 2003) Pa. : 2003), 2006-07, Vol.449 (1), p.57-70
• Main Authors: Zharkova, G. M., Samsonova, I. V., Streltsov, S. A., Khachaturyan, V. M., Petrov, A. P., Rudina, N. A.
• Format: Article
• Language: English
• Subjects: nematic liquid crystal - photopolymer composite; ordered periodic structure; switchable transmission gratings
• ISSN: 1542-1406; 1563-5287
• DOI: 10.1080/15421400600582143

Composite materials with spatially alternating polymer and nematic liquid crystal layers have been obtained. The tetraacrylate pentaerrythritol monomer, methylene blue and nematic liquid crystals were used as the pre-polymer composition. Scanning electron microscopy results show that the supermolecular structure holographically formed in the film depends on the relation between the nematic liquid crystal and dye concentrations in the pre-polymer composition and the curing energy. This system allows preparation of electrically switchable transmission gratings with first-order diffraction efficiencies up to 30-55%. The formed gratings could be switched from diffracting to transparent state at 4.5-7.5 V/μm. The turn-on and turn-off times were 200-300 μs and 1.2-3 ms, depending on the particular composition of the initial composition. Stability of grating characteristics was examined over a 1.5-year period of grating storage.