近期，我院本科生李洁（第一作者），教师吕宁（通讯作者）等的研究成果“Effects of anisotropic sub-millimeter microstructures on condensation and frosting characteristics of superhydrophobic surfaces”在传热传质领域期刊《International Journal of Heat and Mass Transfer》(IF=5.8)上发表
论文简介如下：
超疏水表面结霜初期凝结液滴的生长、合并以及冻结行为，会对后续的霜层生长速率产生重要影响。开发凝结液滴行为的高效调控方法，对强化超疏水表面抑霜效应具有重要意义。本工作采用纳秒激光刻蚀法在铝表面构筑了具有亚毫米尺度的各向异性微结构阵列，并结合浸渍法对具有微结构的金属基底进行全局超疏水改性。通过搭建可视化实验平台，对具有圆柱、三棱柱、长方体等典型拓扑结构的超疏水表面进行凝结-结霜实验，获取了不同表面上液滴的凝结、冻结行为特征，以及冻结波传播速率和后续霜层生长特性，揭示了微结构拓扑对多尺度液滴行为和表面结霜过程的多向作用机制。结果表明，亚毫米尺度微结构能够在凝结液滴群簇生长初期影响小尺寸液滴的合并、弹跳和多液滴合并频率，从而影响群簇尺寸分布；其各向异性则能够在液滴生长后期影响大尺度液滴的空间分布，两者共同影响液滴冻结时间和冻结波传播速率。在三种典型微结构拓扑中，三棱柱微结构具有最好的抑霜效果，相较普通超疏水表面可将表面完全冻结时间延长106.87%，霜层生长速率下降27.59%。
The growth, coalescence and freezing behaviors of condensed droplets during the initial frosting stage on superhydrophobic surfaces significantly influence subsequent growth rate of frost layer height. Developing efficient regulation methods for condensed droplet behaviors is crucial for enhancing the anti-frosting performance of superhydrophobic surfaces. This work fabricated aluminum surfaces featuring anisotropic microstructural arrays at sub-millimeter scale using nanosecond laser ablation, followed by global superhydrophobic modification of the microstructural metal substrates via an immersion method. By establishing a visualization experimental platform, conducting condensation-frosting experiments on superhydrophobic surfaces with typical topologies, including cylinders, triangular prisms and cuboids. The characteristics of droplet condensation and freezing behaviors, freezing front propagation velocity and subsequent frost layer growth properties on these diverse surfaces were obtained. This revealed the multifaceted influence mechanisms of microstructural topology on multi-scale droplet dynamics and surface frosting process. Results demonstrate that sub-millimeter scale microstructures influence frequency of coalescence, coalescence-induced bouncing and multi-droplet coalescence of small-scale droplets during the initial stage of condensed droplet clusters growth, thereby affecting droplet clusters size distribution. Its anisotropy subsequently influences the spatial distribution of large-scale droplets during the later growth stage. Together, these factors influence the droplet freezing time and freezing front propagation velocity. Among the three typical microstructural topologies, the triangular prism microstructure exhibited the most effective anti-frosting performance. Compared with a ordinary superhydrophobic surface, it prolonged the completely freeze time of surface by 106.87% and reduced growth rate of frost layer height by 27.59%.
全文下载：
https://www.sciencedirect.com/science/article/pii/S0017931026001249
