Temperature induced color changing cotton fabricated via grafting epoxy modified thermochromic capsules

A reversible temperature induced color changing cotton fabric had been fabricated via reacting with epoxy modified thermochromic capsule. Epoxy modified thermochromic capsule was prepared by the hydrolysis-polycondensation of siloxane groups of 3-glycidoxypropyltrimethoxysilane (GPTMS) with the hydroxy groups of the capsules. The peaks of epoxy groups in FTIR and the silicon element in XPS demonstrated the GPTMS had been successfully grafted onto thermochromic capsules. The color of epoxy modified thermochromic capsule reversibly turned from blue to white with the color transition temperature of 53 degrees C, and the thermal stability was over 300 degrees C. The thermochromic process was displayed by photos and L*, a*, b* values in a heating-cooling cycle, demonstrating the reversible thermochromic property. The epoxy groups on the surface of thermochromic capsules can react with the hydroxy groups of cotton fabric and form covalent bond. The modified cotton fabrics changed reversibly from blue to white, the same as the capsules that were not bonded to the fabric. The covalent bonding between the fabric and the capsules resulted in excellent washing and rubbing fastness (3-4 grades and 4 grades, respectively).