光热超疏水材料防除冰机理及应用研究进展

Research Progress on Anti-icing Mechanisms and Applications of Photothermal Superhydrophobic Materials

液滴的冻结、积聚往往会对生产、生活造成不利影响,降低设备的运行功效,甚至严重危害生命安全。相较于需要借助外力的主动式防除冰技术,超疏水表面优异的拒水性使其能够实现被动式防除冰,且无需消耗外部能量,从而受到广泛关注。在此基础上,光热超疏水表面结合了主动防除冰和被动防除冰两方面的优势,能在结冰过程的各个时期发挥作用。比如,在结冰前促进液滴的自清除,在结冰时升温表面、延缓成核,在结冰后加速融冰、快速除冰,从而实现节能且高效的固体表面防除冰。概述了超疏水表面的润湿特性和防除冰机理,重点介绍了不同种类光热材料的光热转化机理,包括基于分子热振动的碳纳米光热材料,基于纳米粒子等离激元效应的光热材料,以及基于电子−空穴对非辐射弛豫的半导体光热材料。总结了常用的提高光热转化效率的思路方法,并对比了各类光热超疏水表面在结冰、防冰、除冰及光热响应等方面的性能。最后,针对光热超疏水材料在制备和实际应用中可能存在的问题,分析了未来的发展方向与面临的挑战,为光热超疏水材料的进一步发展与应用提供思路。

The accumulation of frozen liquid droplets often harms industrial production and our daily life,reducing the effectiveness of equipment operation and even seriously endangering life safety.Compared with active anti-icing technologies that require external energy or forces such as hot gas anti-icing and mechanical anti-icing,the excellent water repellency of superhydrophobic surfaces enables passive anti-icing,which is of great interest to both scientists and engineers.With a large water contact angle and small rolling angle,superhydrophobic surfaces ease self-removal of liquids from the surface throughdroplet rolling,jumping or bouncing,thereby holding great prospects for anti-icing and deicing.Starting from the basis of superhydrophobicity,photothermal superhydrophobic surfaces combine the advantages of both active and passive anti-icing,and can be used in all periods of the icing process to achieve energy-efficient and effective anti-icing of solid surfaces.This work provided an overview of the wetting characteristics and anti-/de-icing mechanisms of superhydrophobic surfaces,and focused on the photothermal conversion mechanisms of different types of photothermal materials,including carbon nanophotothermal materials based on molecular thermal vibrations,photothermal materials based on nanoparticle surface plasmon resonance effects,and semiconductor photothermal materials based on electron-hole pair non-radiative relaxation.The ideas and methods commonly used by various types of materials to improve the photothermal conversion efficiency were summarized,and the performance of various types of photothermal superhydrophobic surfaces in terms of icing,anti-icing,de-icing and photothermal response was compared.Finally,the possible problems in preparation and practical applications of photothermal superhydrophobic materials were proposed,and the future development directions and challenges were analyzed to provide insights for further development and applications,including(i)qualitative or quantitative relationship between micro-and nanostructure design of photothermal superhydrophobic surfaces and their anti-icing performance,(ii)robustness and failure mechanisms of photothermal superhydrophobic surfaces,and(iii)facile and low-cost fabrication of photothermal superhydrophobic surfaces and their large-scale practical application.