可控阵列微纳结构超疏水铜表面冰霜传质特性

金属表面粗糙结构及其润湿性对其露、霜、冰的相变及传质现象有重要影响. 通过电火花微加工和化学氧化法，本文首先实现了铜片表面微米、纳米阵列结构的可控制备. 针对条纹，方柱和四棱锥三种典型微米结构特征，对比研究了单级粗糙结构和二级复合结构超疏水表面的润湿性、结露、结霜、结冰及其融化过程. 微纳复合结构可有效增强超疏水性，减少霜晶形核和生长速度，同时还能大幅度延缓结冰的时间，多次冷热循环处理后，表面仍能保持较好的防霜抗冰性能. 通过经典形核理论，Brown 凝并，一维传热及传质理论，综合分析了冰霜在这种表面的传质特性.

Frost and Ice Transport on Superhydrophobic Copper Surfaces with Patterned Micro- and Nano-Structures

Texture and wettability have an important influence on fogging, frosting, and icing on a metal surface. We fabricated micro- and nano-structure patterns on a copper surface by wire electrical discharge machining and subsequent chemical oxidation. By controlling the manufacturing process, three types of microstructure were machined: gratings, pillars, and pyramids. We then studied the wetting performance of the superhydrophobic surfaces with one-tier texture or two-tier texture and the corresponding transport of water in different phase states including fog, frost and icing and their melting processes. Two-tier roughness on the copper effectively improved the superhydrophobicity and retarded the formation and growth of frost. More importantly, these surfaces showed a long delayed icing time, even after several heating and cooling cycles, displaying good resistance to frost and icing. This can be well explained by an understanding of classical nucleation theory, Brown coalescence, and one-dimensional heat and mass transport.