Multifunctional Membrane for Thermal Management Applications

Abstract

Space cooling and heating consume a large proportion of global energy, so passive thermal management materials (i.e., without energy input), especially dual-mode materials including cooling and heating bifunctions, are becoming more and more attractive in many areas. Herein, a function-switchable Janus membrane between cooling and heating consisting of a multilayer structure of polyvinylidene fluoride nanofiber/zinc oxide nanosheet/carbon nanotube/Ag nanowire/polydimethylsiloxane was fabricated for comprehensive thermal management applications. In the cooling mode, the high thermal radiation emissivity (89.2%) and sunlight reflectivity (90.6%) of the Janus membrane resulted in huge temperature drops of 8.2–12.6, 9.0–14.0, and 10.9 °C for a substrate, a closed space, and a semiclosed space, respectively. When switching to the heating mode, temperature rises of 3.8–4.6, 4.0–4.8, and 12.5 °C for the substrate, closed space, and semiclosed space, respectively, were achieved owing to the high thermal radiation reflectivity (89.5%) and sunlight absorptivity (74.1%) of the membrane. Besides, the Janus membrane has outstanding comprehensive properties of the membrane, including infrared camouflaging/disguising, electromagnetic shielding (53.1 dB), solvent tolerance, waterproof properties, and high flexibility, which endow the membrane with promising application prospects.

Slippery Passive Radiative Cooling Supramolecular Siloxane Coatings

“…16,19 This switchability is intrinsically crucial since solar-induced heating is energyfavorable in many conditions, such as winter. 20,21 Self-healing is another valuable property for PRCPCs. It will elongate the service times of coatings by restoring the damages formed on them.…”

Flexible Poly(vinylidene fluoride)-MXene/Silver Nanowire Electromagnetic Shielding Films with Joule Heating Performance

“…So far, compounding polymer matrices with high-conductivity fillers, such as graphene, carbon nanotubes (CNTs), MXene, , and nanowires to prepare conductive polymer composites (CPCs) have been exploited extensively to supplement or substitute inflexible and high-density metal shields. − For example, Cao et al fabricated carbon nanotubes (CNTs)/poly­(vinyl alcohol) (PVA) shielding buckypaper by a vacuum filtration hot press method . The flexible buckypaper exhibited an average effectiveness of 27.08 dB at a CNT content of 83.3 wt %.…”

A review on emerging developments in thermal and moisture management by membrane‐based clothing systems towards personal comfort

“…A dual-mode membrane equipped with both passive radiative heating and cooling performances was reported by Hsu et al 81 They embedded a bilayer emitter inside an IR-transparent PE nanoporous membrane to achieve heating and cooling when the low-emissivity layer faces outside and inside, respectively. Developing bifunctional structures equipped with both radiative cooling and heating performances was also considered by Song et al 61 who produced a Janus membrane with a multilayer structure composed of nanofibrous PVDF layer/ ZnO nanosheet/carbon nanotube (CNT)/silver nanowires (NWs)/polydimethylsiloxane (PDMS). The introduced structure yielded to 10.9 C temperature reduction in cooling mode and 12.5 C temperature increment in heating mode.…”