Visible Temperature Regulation of Phase Change Material Microcapsule‐Incorporated Fibrous Thermochromic Indicator

Textiles incorporating microencapsulated phase change material (MPCM) offer intelligent temperature regulation and enhanced wearing comfort by buffering external temperature fluctuations. Real‐time temperature monitoring of such phase‐change material (PCM) textiles is essential for delivering objective temperature data and alerting wearers to ambient conditions. While thermochromic MPCM coatings have been explored for this purpose, challenges remain in controlling the relationship between thermochromic and phase change temperatures and in ensuring uniform coating distribution. In this work, MPCM‐incorporated fibrous thermochromic indicators were prepared by applying an MPCM/thermochromic pigment coating onto a hydrophobic fibrous substrate using the blade coating method. As a result, the MPCM/thermochromic pigment coating is uniformly deposited on one side of the hydrophobic fibrous substrate. The phase transition and thermal energy storage behavior of the MPCM are independent of the thermochromic pigment. The MPCM‐incorporated fibrous thermochromic indicators exhibit stable thermochromic properties from 22 to 34 °C and effective thermal energy storage between 24 and 29 °C. The enthalpy of the MPCM‐incorporated fibrous thermochromic indicator exceeds 12 J g −1 , with MPCM contribution over 80%. The MPCM‐incorporated fibrous thermochromic indicators also exhibit a significant thermal buffering effect, serving as a dual‐function platform for temperature management and visual temperature warning, with promising applications.