辐射冷却材料的制备方法综述

Review on the Preparation Methods of Radiative Cooling Materials

随着能源和环境问题的日益严重,不需要额外消耗能量的辐射冷却技术引起了广泛关注。基于地球和宇宙的巨大温差,辐射冷却技术能够直接将热量以辐射的形式传递到外太空,不仅能够产生净冷却效果,而且避免了废热排放带来的诸多环保问题。早期研究利用涂敷法将具有辐射冷却能力的涂料刷涂在物体表面,该方法仅能实现材料的夜间降温。为了实现材料的日间辐射冷却则需要在其中引入特定结构,如多层膜结构、二维光子晶体结构、超结构等以提高它的可见近红外波段的反射率和大气窗口的发射率。然而,相关制备技术存在工艺复杂、制备成本高、难以宏量制备等局限性,严重阻碍了辐射冷却材料工程应用的推进。随着辐射冷却理论研究的深入以及更多先进制备技术的发展,制备方法和手段也越来越多样化,如真空蒸镀、微纳米加工技术、直接涂敷法、挤出成型技术、静电纺丝法等相继被报道,通过这些方法能够低成本地制备出较大面积的辐射冷却材料,进一步推动了辐射冷却材料及技术的应用。本文归纳了辐射冷却材料制备方法的研究现状,对不同制备技术的优缺点进行了对比分析。首先概述了辐射冷却常用材料及其成型方式;然后介绍了辐射冷却材料常用制备方法及各自优缺点,简述了适用于特殊材料或应用场景的制备方法;最后总结了目前辐射冷却材料制备存在的问题并展望了未来的发展方向。

In recent years,with the worsening of energy and environmental problems,the radiative cooling technology which can cool the object without energy consumption has attracted worldwide attention.This cooling technology uses the extract temperature difference between the earth and the universe to transfer heat directly to outer space in the form of radiation without energy input,which is able to avoid many energy and environmental problems caused by waste heat.Early researches brushed the paint with radiative cooling ability on the object surface,which can only achieve cooling effect at night.In order to achieve radiative cooling during daytime,it is generally necessary to introduce materials with specific structures,such as multilayer film structure,two-dimensional photonic structure,meta-structure,etc.However,the as-prepared material has disadvantages such as high cost,low yield,small area which seriously hinder the practical application of radiative cooling materials.With the development of radiative cooling theory and the maturation of advanced manufacture techniques,the preparation methods of radiative cooling materials are becoming more and more diversified.Vacuum evaporation,micro-nano processing technology,direct coating,extrusion molding and electrospinning have been reported.Large area radiative cooling materials can be prepared at low cost,which further promotes the commercial application of radiative cooling technology.This review summarizesresearch status of radiative cooling materials preparation,compares the advantages and disadvantages of different preparation methods.First,the common radiative cooling materials and forming methods are summarized;then the widely used preparation methods of radiative cooling materials are introduced and their characteristics are analyzed.After that the fabrication methods chosen by the researchers for specific materials or application scenarios are summarized.Finally current problems and future development perspectives of the preparation of radiative cooling materials are discussed.