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http://dx.doi.org/10.14478/ace.2019.1002

Effect of 2-HEA and EGPA Composition on the Electro-optical Properties of Polymer Dispersed Liquid Crystal  

Choi, Jongseon (Graduate school of Energy Science and Technology, Chungnam National University)
Kim, Young Dae (Graduate school of Energy Science and Technology, Chungnam National University)
Kim, So Yeon (Graduate school of Energy Science and Technology, Chungnam National University)
Publication Information
Applied Chemistry for Engineering / v.30, no.2, 2019 , pp. 205-211 More about this Journal
Abstract
Over the past several decades, the polymer dispersed liquid crystal (PDLC) has received particular attention as a material for developing smart window due to their electro-optical switchable properties. In this study, PDLC cells were fabricated using acrylate monomers, namely 2-hydroxyethyl acrylate (2-HEA) and ethylene glycol phenyl ether acrylate (EGPA), and the effect of the monomer composition on their electro-optical properties was investigated. The monomer mixture with a low viscosity (~10 cps) was easily filled between indium tin oxide (ITO) glasses by capillary action at room temperature. PDLC cells prepared using the mixture ratio of 1 : 9 (2-HEA : EGPA) did not show a complete opaque state at a 0 V condition but exhibited unstable electro-optical properties under an electric field. As the LC composition increased in the reaction mixture for PDLC cell preparation, the $V_{th}$ (threshold voltage) and $V_{sat}$ (saturation voltage) values as well as contrast ratio (CR) increased. $V_{th}$ and $V_{sat}$ values also increased with the cell gap thickness. PDLC cells with a $20{\mu}m$ cell gap thickness exhibited higher CR than those with 10 and $40{\mu}m$ cell gap thicknesses. Particularly, PDLC cells prepared using the mixture ratio of 7 : 3 (2-HEA : EGPA) showed excellent electro-optical properties such as a low driving voltage and high contrast ratio.
Keywords
Polymer dispersed liquid crystal; Smart window; 2-HEA; EGPA; Electro-optical properties;
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