Adaptive Thermal Protective Skin Based on Water Transportation and Transpiration for Extremely Rapid Cooling Applications

A flexible thermal protective system is highly desirable for maintaining the safety of the human body or spacecraft with complex profiles. However, it is still challenging to attain high deformability and rapid cooling, especially with intense chemical fire or aerodynamic heat. Inspired by the sweat gland of human skin, herein an adaptive two-layered skin is developed based on inner hollow porous TPU/PVC fibers embedded in silicone for water transportation and outer PET spacer fabric for water storage and transpiration. The TPU/PVC hollow fibers were optimized with good superhydrophilicity, high porosity of 79%, and excellent deformability (∼303%). The adaptive thermal protective skin (∼5 mm) shows good biaxial deformability (∼150%) and attains a comfortable temperature (∼46 °C) under high heat flux (420 kW/m2) within 1 s. Finite element simulation reveals that the spacer fabric with an optimized thickness of 9 mm can reduce the 1000 °C surface temperature to 20 °C in 0.7 s. We believe that this adaptive thermal protective skin paves an effective way to achieve rapid cooling for the human body, robotics, and spacecraft under extreme heat environments.