Optimization of LC droplet size and electro-optical properties of acrylate-based polymer-dispersed liquid crystal by controlling photocure rate


Correspondence to: J.-W. Hong (E-mail: jhhong@chosun.ac.kr)


We investigated the effects of the different content ratios of 2-ethylhexylacrylate (2-EHA) and 2-ethylhexylmethacrylate (2-EHMA) on the relationships among the photopolymerization rate, morphology of liquid crystals (LCs) droplets, and electro-optical properties of trifunctional urethane acrylate-based polymer-dispersed liquid crystal (PDLC) systems. Photo-differential scanning calorimetry (DSC) analysis and resistivity measurement revealed that increasing 2-EHMA content gradually decreased the photocure rate of trifunctional urethane acrylate-based PDLCs, which prolonged the phase separation between the LC molecules and the prepolymers. Morphological observations and electro-optical measurements demonstrated that trifunctional urethane acrylate-based PDLCs with the 2-EHA:2-EHMA ratios from 4:1 to 3:2 in weight percent formed the favorable microstructures of LC droplets being within the range of 1–5 µm to scatter light efficiently and showed the satisfactory off-state opacity and on-state transmittance and the relatively low-driving voltage. The microstructures of LC droplets and electro-optical properties of trifunctional urethane acrylate-based PDLCs could be usefully optimized by controlling the photocure rate using the different 2-EHA/2-EHMA content ratios. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3098–3104, 2013