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Park S.,Q SyS Co. | Kim H.-K.,Chosun University | Hong J.W.,Chosun University
Polymer Testing | Year: 2010

A novel experimental method involving simultaneous resistivity and transmittance measurements was used to examine the polymerization-induced phase separation process. Measuring the resistivity and transmittance of a polymer dispersed liquid crystal (PDLC) cell allows the polymerization and phase separation to be monitored during the PDLC formation process. To verify the utility of this method, resistivity data were compared with conversion data obtained by photo differential scanning calorimetry (DSC) and FTIR analysis using NOA65 and an NOA65-E7 mixture. The resistivity data of NOA65 (a neat prepolymer without liquid crystals) were identical to the conversion data obtained by photo-DSC and FTIR analysis. However, the resistivity data of the NOA65-E7 mixture (a prepolymer with liquid crystals) differed from the conversion data because the resistivity of the NOA65-E7 mixture was affected by the degree of liquid crystal phase separation and monomer conversion. The photopolymerization was slower and the degree of conversion was higher for the NOA65-E7 mixture than for the neat prepolymer due to dilution and plasticization effects, respectively. © 2010 Elsevier Ltd. All rights reserved.

Q. SyS Inc. | Date: 1997-04-22

computer systems, comprising computer hardware and software that interfaces with telephony equipment, namely public access branch exchange (PABX), all for use in computer telephone integration.

This invention relates to a polymer dispersed liquid crystal type light control body using a nickel deposited electrode or a nickel-chromium alloy deposited electrode instead of an existing indium tin oxide electrode, including: two electrode substrates having electrodes, and a light control layer formed between the two electrode substrates, wherein at least one of the two electrode substrates includes a nickel-based electrode. The light control body can exhibit superior near-infrared blocking effects in ON state, and can also manifest peel adhesion strength, pendulum hardness of a film, haze and contrast ratio adapted for commercial applications thereof, ultimately achieving energy saving performance due to heat ray blocking effects as well as cost reductions.

Park S.,Q SyS Co. | Kim Y.B.,Q SyS Co. | Cho J.D.,Q SyS Co. | Lee S.S.,Q SyS Co. | And 2 more authors.
Proceedings of International Meeting on Information Display | Year: 2010

Polymer-dispersed liquid crystal (PDLC) films were used for the electro-optical modulator for the sensor in TFT array tester. PDLC films with high uniformity were made by precision roll-to-roll coating and photopolymerization-induced phase separation processes. Electro-optical factors in PDLC film affecting the inspection quality were examined.

Cho J.-D.,Q SyS Co. | Lee S.-S.,Q SyS Co. | Kim Y.-B.,Q SyS Co. | Hong J.-W.,Chosun University
Macromolecular Research | Year: 2013

This paper reports on the relationship between the photocure kinetics and the morphological properties of UV-curable acrylate-based polymer dispersed liquid crystal (PDLC) systems with the various 2-ethylhexylacrylate (2-EHA) and 2-ethylhexylmethacrylate (2-EHMA) contents using photo-differential scanning calorimetry (photo-DSC), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). Photo-DSC analysis using an autocatalytic kinetics model demonstrated that the cure extent and cure rate gradually decreased and then leveled off as the concentration of 2-EHMA increased up to 25 wt%, which was well confirmed by using FTIR spectroscopy. The morphological observations revealed that increasing the 2-EHMA content increased the size of the LC droplets within the acrylate-based polymer matrix. Notably, there was a marked increase in the number of LC droplets larger than 10 μm in PDLC composites containing more than 20 wt% 2-EHMA, suggesting that the addition of more than 20 wt% 2-EHMA to the acrylate-based PDLC compounds is not desirable. The presence of 2-EHMA clearly affected the photocure behaviors of acrylate-based PDLC compounds, which interestingly means that the slow reactivity of methacrylate monomer could be simply used to control the phase separation rate and the microstructures of LC droplets of acrylate-based PDLC systems. © 2013 The Polymer Society of Korea and Springer Sciene+Business Media Dordrecht.

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