Scalable Film Based on Thermochromic and Radiative\nCooling Effects for Anti-Counterfeiting and Low Temperature Preservation

Thermochromism and radiative cooling\nhave received extensive attention\nas two popular research areas in recent years. However, how to effectively\ncombine the two remains a challenge. Herein, we present a well-designed\npolymethylpentene (TPX)/silicon dioxide (SiO<sub>2</sub>)/thermochromic\nmicrocapsule (TSTM) hybrid film, which effectively integrates both\nthermochromic and radiative cooling capabilities. Notably, the thermochromic\ncapability gives the TSTM film excellent anticounterfeiting performance\nby inducing a temperature-dependent change in solar transmittance.\nFurthermore, the TSTM film exhibits a high average infrared emittance\n(ε̅IR) value of ∼94% at low temperatures\nand achieves a cooling effect exceeding 5C under a solar intensity\n(<i>I</i><sub>solar</sub>) of ∼900 W m<sup>–2</sup>, indicating an excellent radiative cooling property and potential\nfor effective low-temperature preservation under sunlit conditions.\nAdditionally, the TSTM film demonstrates outstanding durability, while\na simple and straightforward fabrication process allows for large-scale\nproduction. Such a scalable, durable, and dual-functional hybrid film\ndemonstrates an innovative and effective design, holding promise for\nexpanding its application in the fields of anticounterfeiting and\nlow temperature preservation.