Preparation and properties of polychromatic liquid crystal microcapsules

Nematic phase liquid crystal mixture with chiral dopant was synthesized to replace cholesteric liquid crystal as the core of microcapsule. Firstly, series of liquid crystal mixture color-changed at room temperature were prepared by adjusting the different ratios of nematic liquid crystal and chiral additive. Afterwards, three extra additives were explored respectively as the addition of the polychromatic liquid crystal mixture to determine the best formulation of liquid crystal mixture displaying different color at varied temperature. A series of liquid crystal microcapsule were conducted and refined by isophorone diisocyanate (IPDI) filled with the above liquid crystal mixture (i.e. the core of micro capsule) in terms of interfacial polymerization reaction. It can be concluded from the characterization that the best liquid crystal microcapsules size range between 50-105 mu m with average particle size of 68.06 mu m and the contents of core materials is about 35%. The microcapsules exhibit spherical with uniform particle size and good temperature change color performance simultaneously. In addition, thermal decomposition temperature of 330 degrees C confirms the better thermal stability of liquid crystal microcapsules in this work.