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Repeated disordered structure for radiative cooling application via scalable stamping method from designed CaCO3 templates
Author(s)
Kaewmanee, Taweesak
Sakata, Patawee
Gridtayawong, Pharit
Rueangsawang, Worawut
Ponghiransmith, Chattrarat
Chattham, Nattaporn
Noinonmueng, Tanisara
Benchaphanthawee, Wachara
Kaewkhao, Jakrapong
Suttiruengwong, Supakij
Kanjanaboos, Pongsakorn
Date Issued
July 1, 2026
Type
Article
Abstract
Radiative cooling via micro-patterned surfaces provides energy-efficient solution for thermal regulation by enhancing selective thermal emission within the atmospheric transparency window (8–13 μm). This study investigates the effects of microstructural patterning through a low-cost and scalable stamping technique. The patterning templates were uniquely produced by the removal of randomly-distributed CaCO3 polymorphs—calcite and vaterite with specific sizes. The novel calcite-imprinted structures exhibit superior mid-infrared emissivity (>0.96) and maintain consistent temperature reduction across varying weather conditions, outperforming vaterite-based films. However, the cooling performance of unmodified patterns is limited by solar absorption. To address this, TiO2 (rutile phase) is incorporated into a polymer matrix before being stamped to enhance solar reflectivity. Moreover, hydrophobic aerogels could be inserted between micropattern gaps to facilitate self-cleaning functionality. A composite film containing 3 wt% TiO2 with the calcite micro-patterning and hydrophobic aerogel achieves a temperature drop of 4.8 °C, compared to 1.2 °C of pristine patterns relative to that of a clear film. For real-world applicability, the optimized patterning strategies were further validated on fiber cement rooftile surfaces, yielding best temperature reductions of 2.5 °C compared to pattern-free coating under a tropical climate. The calculated net cooling power of 3 wt% TiO2 patterned film with aerogel is 26.9 W/m2. This novel passive-cooling stamping strategy is low-cost, scalable, and suitable for large-area deployment, reducing the energy burden of active cooling technologies.
Citation
Applied Thermal Engineering, 299, 2026