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Transmission Holographic Polymer Dispersed Liquid Crystals Based on a Siloxane Polymer
Author(s) -
Woo Ju Yeon,
Kim Eun Hee,
Kim Byung Kyu
Publication year - 2008
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200700521
Subject(s) - materials science , polymer , liquid crystal , fabrication , coalescence (physics) , siloxane , diffraction efficiency , chemical engineering , diffraction , phase (matter) , optics , composite material , optoelectronics , organic chemistry , chemistry , grating , medicine , alternative medicine , physics , pathology , astrobiology , engineering
Abstract The low surface energy and the great immiscibility of poly (dimethylsiloxane) (PDMS) with liquid crystals (LCs) are used in the fabrication of holographic polymer dispersed liquid crystals (HPDLCs). By adding increasing amounts of PDMS, the extent of the phase separation between the polymer and the LC, the LC channel width, and—eventually—also the diffraction efficiency of the film can be increased, while keeping the droplet size essentially the same. In addition, the presence of PDMS causes a decrease in the switching voltage and an increase in the response time. At an optimum content of PDMS (PUA40), a minimum switching voltage of 4 V μm −1 , a rise time of 0.20 ms, and a decay of 14.75 ms were obtained. Regarding the effect of the LC content, an overshoot of the diffraction efficiency was observed when the amount of LC exceeded 35 %, which can be attributed to droplet coalescence.