| The prepatarion methods and research development of liquid crystal microcapsules are introduced in this paper. The thermochromic effect of cholesteric liquid crystals is also studied.In this study, a kind of thermochromic liquid-crystal/polyurea microcapsules was prepared by using interfacial polymerization. We used polyurea as the wall and cholesteric liquid crystals as the core. The principle of polymerization is that the isocyanate can react with water and form amine which reacts quickly with unreacted isocyanate and forms polyurea. The factors in microcapsules preparation were studied, and the results that the optimized method is:the volume ratio of liquid crystal and IPDI is 1:2, then poured the mixture into 2%wt PVA aqueous solution and emulsified with a homogenizer at 2000rpm for 10 min. After adding the DBTDL (0.05ml) into the system, the emulsion was stirred with 600rpm at 40℃for 6 hours. The microcapsules were very spherical with smooth surfaces, and had a certain particle size distribution range (0.5 micron-12 micron).The color properties of cholesteric liquid crystals were also studied. The chiral dopant S811 was added into nematic liquid crystal TEB30A with different concentration, to form cholesteric liquid crystal with different pitch. The cholesteric liquid crystal displayed red, green and blue color, respectively when the contents were 18%,22%, and 27%. The cholesteric liquid crystal was sensitively changed with temperature and displayed bright colors. The color range can be changed with the amount of choleteryl acetate when mixing together.
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