Print: | ISSN 0256-1115 |
Online: | ISSN 1975-7220 |
Korean Journal of Chemical Engineering,
Vol.25, No.1, 181-184, 2008 Temperature stability of electro-optic properties of polymer dispersed liquid crystal with different crosslinking monomer in PN393 base pre-polymer
The electro-optic properties of polymer-dispersed liquid crystals (PDLCs) fabricated by photo-induced phase separation have been investigated. A mixture of TL205 (80 wt%) liquid crystal and PN393 (20 wt%) pre-polymer having different crosslinking monomers was used for producing various PDLCs to compare its temperature stability. As a reference, a commercialized PN393 formulation was closely examined to compare the effects of replacing the crosslinker. The liquid crystal domain size varied from 3.5mm to 10.3 μm depending on the crosslinker used. The larger domain size of PDLCs consisting of vinyl ether shows higher contrast ratio but faster response time and higher turnon voltage, which is contrary to the prediction. Acrylate-based PDLCs were found to be turned on, although abruptly increasing below 20 ℃, and also showed heavy variation of other electro-optic over a wide operation temperature range. By substituting a vinyl-ether for the acrylate crosslinker, the temperature behavior was greatly improved.
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