Adaptive Radiative Cooling and Thermal Insulation Enabled by Thermoresponsive Cholesteric Liquid Crystal Aerogels

Abstract

Adaptive radiative cooling has received increasing attention for passive thermal management, especially under fluctuating environmental conditions. However, most reported adaptive materials, such as phase transition materials, still face challenges including abrupt switching, limited spectral controllability. Here, a porous cellulose aerogel filled with thermoresponsive cholesteric liquid crystals (CLCs) was successfully prepared to achieve continuously tunable adaptive radiative cooling with reversible and phase-transition-free thermal regulation. The composite aerogel with an optimized concentration of temperature-sensitive chiral dopants exhibits temperature-dependent modulation of reflectivity and emissivity, reaching a high solar reflectivity of ~87% and an infrared emissivity exceeding 98% within the atmospheric window. Benefiting from thermally induced modulation of the cholesteric helical pitch, the composite aerogel delivers effective daytime radiative cooling with a maximum temperature reduction of 8.5 °C below ambient under ~575 W m⁻² solar irradiation, while maintaining an average temperature approximately 0.5 °C above ambient at nighttime. Simulated storage and insulation tests further demonstrate its ability to stabilize internal temperature and resist external thermal disturbances without external energy input. This work introduces cholesteric liquid crystal aerogels as a new class of adaptive radiative cooling materials and establishes a general photonic-structure-based design strategy for intelligent, all-day passive thermal management, with strong potential in energy-efficient buildings, outdoor electronics protection, and temperature-sensitive goods storage and transportation.