Preparation and characterization of thermotropic liquid crystal microcapsules and application in textile

In this paper, thermotropic liquid-crystal microcapsules of cholesteric liquid crystal (CLC) as core material and melamine-formaldehyde (M-F) as shell material were prepared via in-situ polymerization. The core material of CLC herein was mixture of cholesteryl oleyl carbonate (COC) and cholesterol pelargonate (CPE). The optimal preparation conditions were assured based on the serial trial experiments. It was found that the prepared CLC microcapsules had spherical shape and smooth surface, and the mean particle size was about 8-10 μm. The FT-IR spectra and SEM images confirmed that the M-F shell was successfully fabricated on the surface of CLC core material. Finally, the CLC microcapsules were treated on the fabric, and the treated fabric showed color change between 33.4 °C and 38.0 °C, which is appropriate for human comfortable feeling. CIE L*a*b* values were obtained, and it confirmed the treated fabric had good color change performance. In this paper, the cholesteric liquid crystal (CLC) showed its excellent ability to change color, and the experiment result also proved that CLC microcapsules for preparing thermotropic fabric is reasonable and practicable.