Change of Electro-optical Properties of Polymer Dispersed Liquid Crystal Lens with Addition of Extra Photo-initiator

• Journal title : Korean Chemical Engineering Research
• Volume 52, Issue 3,  2014, pp.321-327
• Publisher : The Korean Institute of Chemical Engineers
• DOI : 10.9713/kcer.2014.52.3.321
Title & Authors
Change of Electro-optical Properties of Polymer Dispersed Liquid Crystal Lens with Addition of Extra Photo-initiator
Kim, Jaeyong; Han, Jeong In;

Abstract
Polymer dispersed liquid crystal lenses of the cell gap of $\small{11{\mu}m}$ and $\small{30{\mu}m}$ were made from a uniformly dispersed mixture of 40 wt% NOA65 prepolymer - 60 wt% E7 liquid crystal with the variations of the additional photoinitiator. The photoinitiator, benzophenone of 5.0 wt% was originally in the commercial prepolymer NOA65. In this works, the influence of the benzophenone amount intentionally added in the commercial NOA65 on the electrical properties of polymer dispersed liquid crystal lens for smart electronic glasses. The additional quantities of the photoinitiator were 1, 2, 4, 8 and 16 wt% of the weight of NOA65 - E7 mixture. All the electro-optical properties of the sample with added benzophenone such as the driving voltage, the slope of the linear region, the response time and contrast ratio were more improved than that of commercial NOA65 only. These improvements were due to the increase of the average size of E7 liquid crystal droplets in the samples with the increase of the added benzophenon amount. The liquid crystal droplet size was increased from $\small{5.3{\mu}m}$ to $\small{12.2{\mu}m}$ when the photoinitiator was added from 0 wt% to 8 wt%. At the same concentration range of the photoinitiator, the driving voltage was ranged from 11.1 V to 17.3 V. The slopes of the linear region were in the range of 10.35~13.96 %T/V, which were more enhanced than that of NOA65 without the additional benzophenone. In particular, though the deteriorations by cell gap of $\small{11{\mu}m}$ were so effective to offset the influence of the added benzophenone for both rising and falling response time, it is confirmed that there were still somewhat improvement by the additional benzophenone. Response time and contrast ratios of all the samples with excess benzophenone were slightly enhanced.
Keywords
Polymer Dispersed Liquid Crystal(PDLC);Benzophenone;Photoinitiator;Smart Electronic Glasses;
Language
Korean
Cited by
1.
수산기로 치환된 벤조페논 그룹의 자외선 차단 소프트 콘택트렌즈로의 응용,김득현;성아영;

대한시과학회지, 2015. vol.17. 1, pp.57-68
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