All-in-one: Janus-structured films comprising protonated covalent organic nanosheets for adaptive all-weather personal thermal management

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2025-01, Vol.503, Article 158287
• Main Authors: Chen, Guinan, Lou, Yuanyuan, Chen, Liangjun, Zhang, Tao, Liang, Yi, Zhou, Guangshan, Luo, Guanglun, Gu, Dawei, Zhang, Guang, Peng, Yongwu
• Format: Article
• Language: English
• Subjects: Asymmetric photothermal property; Janus-structured; Personal thermal management; Protonated covalent organic framework nanosheets
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.158287

A protonated covalent organic nanosheets (CON)-derived Janus-structured film has been engineered with tunable thermoregulatory properties, enabling selective control over solar-thermal heating and anti-solar cooling. [Display omitted] •Protonated COF nanosheets show enhanced solar heating, enabling Janus films fabrication with asymmetric architectures.•Contrasting infrared reflectivity of Janus films ensures superior personal thermal management.•Silver nanowires enable controllable electrical heating in extreme cold and low-light conditions.•Janus films exhibit air permeability, flexibility, and waterproofing for versatile applications. Effective temperature-regulating materials are essential for personal thermal comfort in challenging climatic conditions. Protonated covalent organic framework nanosheets (CONs), known for their high light absorption, low thermal conductivity, and enhanced processability, have been underexplored in this domain. Here, we present Janus-structured films with notable asymmetric photothermal properties and exceptional Joule heating capabilities, advancing personal thermal management strategies. By integrating protonated CONs and aramid nanofibers (ANFs) with opposite infrared reflectivity on either side of a conductive silver nanowires (AgNWs) film, the resulting CONs/AgNWs/ANFs film features a Janus architecture. This design maintains the CON-side temperature approximately 7 °C higher than bare skin, and 14 °C higher than the ANF-side under 0.5 sun irradiation, facilitating adaptable photothermal regulation. Additionally, the incorporation of AgNWs enables remarkable Joule heating capabilities, reaching saturation temperatures up to 195 °C within 15 s with input voltages ranging from 0.4 to 1.2 V. These Janus-structured films, with customizable photothermal properties and superior electrothermal performance, show significant promise for precise personal thermal management, facilitating controlled and comprehensive body temperature regulation.