Eberle Patric, Tiwari Manish K, Maitra Tanmoy, Poulikakos Dimos
Laboratory of Thermodynamics in Emerging Technologies, Mechanical and Process Engineering Department, ETH Zurich, 8092 Zurich, Switzerland.
Nanoscale. 2014 May 7;6(9):4874-81. doi: 10.1039/c3nr06644d.
Icing of surfaces is commonplace in nature, technology and everyday life, bringing with it sometimes catastrophic consequences. A rational methodology for designing materials with extraordinary resistance to ice formation and adhesion remains however elusive. We show that ultrafine roughnesses can be fabricated, so that the ice nucleation-promoting effect of nanopits on surfaces is effectively counteracted in the presence of an interfacial quasiliquid layer. The ensuing interface confinement strongly suppresses the stable formation of ice nuclei. We explain why such nanostructuring leads to the same extremely low, robust nucleation temperature of ∼-24 °C for over three orders of magnitude change in RMS size (∼0.1 to ∼100 nm). Overlaying such roughnesses on pillar-microtextures harvests the additional benefits of liquid repellency and low ice adhesion. When tested at a temperature of -21 °C, such surfaces delayed the freezing of a sessile supercooled water droplet at the same temperature by a remarkable 25 hours.
表面结冰在自然、技术和日常生活中很常见，有时会带来灾难性后果。然而，设计具有非凡抗结冰和抗粘附性能材料的合理方法仍然难以捉摸。我们表明，可以制造出超细粗糙度，从而在存在界面准液体层的情况下有效抵消纳米坑对表面冰核形成的促进作用。随之而来的界面限制强烈抑制了冰核的稳定形成。我们解释了为什么这种纳米结构在均方根尺寸（约0.1至约100纳米）变化超过三个数量级的情况下，会导致相同的极低且稳定的成核温度，约为-24°C。在柱状微纹理上叠加这种粗糙度可获得液体排斥性和低冰粘附性的额外好处。在-21°C的温度下进行测试时，这种表面将同温度下静止的过冷水滴的冻结显著延迟了25小时。
