Phase-Change Material-Integrated Dual-Mode Thermal Management Janus Films with Enhanced Radiative Cooling and Solar Heating

Passive radiative cooling (PRC) and solar heating (SH) are highly desired in a variety of areas such as personal thermal regulation and thermal control of a building's macroenvironment. However, most current thermal management materials are usually a single function with static temperature regulation, resulting in a poor feature with environment adaption. Here, a phase-change material-integrated dual-mode Janus film with enhanced radiative cooling and SH for thermal management is demonstrated. The Janus film is developed by integrating a paraffin-type phase-change material (PCM) and carbon nanotube (CNT)-modified poly(dimethylsiloxane) (PDMS), enabling both PRC and SH. The cooling mode of Janus film is achieved by infrared ray thermal radiation of PDMS and absorbing heat of PCM. The heating mode of Janus film is achieved by SH of the CNTs@PDMS layer, and solar energy is converted into heat energy stored and released by PCM@PDMS. The introduction of PCM enhances the practical effects of radiation cooling and SH. The energy storage of PCM can be released at night, avoiding unwanted overcooling. In addition, the PCM@PDMS features self-cleaning and self-repair abilities. This work provides a PCM-enhanced dual-mode thermal management strategy toward applications in a practical scenario with dynamic ambient temperature variations.