利用温度敏感型水凝胶进行仿生发汗冷却

温度敏感型水凝胶能够在较低临界溶解温度附近发生体积相变，吸收或释放出大量水分。利用这一特性，可以对过热物体实现仿生发汗冷却。通过光学干涉方法，测量了水凝胶发汗冷却时的温度、湿度分布和散热特性，验证了其仿生散热数值模型；并利用该模型进一步研究了不同环境温度、环境湿度和相变释水温度对水凝胶散热能力的影响。结果表明，水凝胶发汗冷却的传热系数为经典被动散热方法（自然对流与热辐射）的15～25倍，能迅速降低试件表面温度。随着环境温度、相变释水温度的提高，传热系数进一步显著提高；随着环境湿度的提高，传热系数略有下降。由于无需风扇就能获得巨大散热能力， 水凝胶仿生散热技术对于手机等微电子设备的散热具有重要意义。

Bio-mimic transpiration cooling using temperature-sensitive hydrogel

Temperature-sensitive hydrogel (TSHG), a smart macromolecular material releasing moisture automatically when its temperature exceeds the lower critical solution transition temperature (LCST), has been used for transpiration cooling, mimicking the thermoregulation mechanism of living creatures.The temperature and humidity distributions and heat dissipation characteristics of the TSHG transpiration cooling were measured experimentally using laser interference technique.A numerical model was established and verified with the experimental results.With the numerical model, the effects of environmental temperature, environmental humidity and LCST on the heat dissipation capability of TSHG were further studied.Results show that the cooling of TSHG can quickly lower the temperature of the specimen, with a heat transfer coefficient 15 to 25 times larger than that with common passive heat dissipation methods (natural convection and thermal radiation).The heat transfer coefficient can be significantly increased with the increase of environmental temperature and LCST, and may be slightly declined with the increase of environmental humidity.With the high heat dissipation rate without using a fan, the TSHG transpiration cooling is promising for the thermal management of mobile phones and other portable microelectronics.