Preparation and study of polydimethylsiloxane/polytetrahydrofuran blended soft‐segment‐based passive cooling polyurethane materials.

This study introduces a series of novel passive‐cooling polyurethane materials (SiTPUs) by incorporating hydroxybutane‐terminated polydimethylsiloxane (OH‐PDMS)/polytetrahydrofuran (PTMG)‐mixed soft segments. Wide‐angle x‐ray scattering (WAXS) and small‐angle x‐ray scattering (SAXS) analyses revealed that with an increase in the OH‐PDMS content, the material exhibited enlarged grain sizes, reduced crystallinity, and the formation of larger‐sized microphase "structures with different compatibilities. The sample with a PDMS proportion of 40% (SiTPU‐40) demonstrates outstanding passive cooling performance, achieving a reflectance of 70.2% in the solar spectrum and a high atmospheric window emissivity of 91.6% without needing metal additives, resulting in a cooling effect of 10.8°C compared with that of pure thermoplastic polyurethane (TPU). Static contact angle tests indicated that introducing OH‐PDMS considerably enhanced the self‐cleaning performance of the material, with a PDMS proportion of 50% (SiTPU‐50) achieving the highest contact angle of 112°. Overall, this multi‐soft segment design optimizes passive cooling performance and enhances self‐cleaning capabilities, thus offering new possibilities for extensive material applications, especially in wearable technology and architectural surface coatings. [ABSTRACT FROM AUTHOR]