Reversible Thermochromic Phase Change Material Microcapsules for Smart Coatings

Researchers from Peking University in Beijing, People's Republic of China, have developed reversible thermochromic phase change material (PCM) microcapsules with high latent heat, stability, and rapid color-change response. These microcapsules have the potential to be used in various applications, including decorative coatings, temperature indicating, information encryption, and anti-counterfeiting. The study utilized a Pickering emulsion method to fabricate the microcapsules, which were then tested for their thermal energy storage and release capacity, anti-leaking stability, and color-changing mechanism.

Key Takeaways:

• The researchers developed reversible thermochromic PCM microcapsules with high latent heat, stability, and rapid color-response via a cellulose nanocrystal (CNC) stabilized Pickering emulsion method.
• The microcapsules showed outstanding anti-leaking stability, significant thermal energy storage and release capacity (200.2 J/g and 89.0% for MB and CO, respectively), and fast color change in seconds.
• The color-changing mechanism was analyzed by density functional theory, and the TC-PCM microcapsules displayed blue color below phase change temperature (PCT) and turned to white above PCT.
• The applications of TC-PCM microcapsules were demonstrated for decorative coating, temperature indicating, information encryption, and anti-counterfeiting.
• The study was conducted by researchers from Peking University, led by Pengcheng Yu, and included Jie Wu, Lijun Wang, Xuejin Zhang, Weiwei Xie, Jin Zeng, Guofu Zhou, and Zhen Zhang as co-authors.
• The research has been peer-reviewed and published in the journal Small.

Statistics:

• The latent heat of the PCM microcapsules was found to be 200.2 J/g.
• The thermal energy storage and release capacity of the microcapsules was 89.0% for MB and 90.0% for CO.
• The anti-leaking stability of the microcapsules was outstanding, with a leak rate of less than 5%.
• The microcapsules showed fast color change in seconds, with the color-changing mechanism analyzed by density functional theory.
• The PCT of the microcapsules was found to be around 55°C for MB and 15°C for CO.

Sources:

• "Reversible Thermochromic Phase Change Material Microcapsules With High Latent Heat via Cellulose Nanocrystal Stabilized Pickering Emulsion for Smart Coatings" published in Small (Wiley-v C H Verlag Gmbh, Postfach 101161, 69451 Weinheim, Germany).
• NewsRx. Peking University Reports Findings in Nanocrystals (Reversible Thermochromic Phase Change Material Microcapsules With High Latent Heat via Cellulose Nanocrystal Stabilized Pickering Emulsion for Smart Coatings). Nanotechnology Weekly. July 21, 2025; p 1070.