Phase-Change Slippery Liquid-Infused Porous Surfaces with Thermo-Responsive Wetting and Shedding States
Phase-Change Slippery Liquid-Infused Porous Surfaces with Thermo-Responsive Wetting and Shedding States
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DOI：
10.1021/acsami.0c06441
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发表时间：
2020-07-29
影响因子：
9.5
通讯作者：
Zhang, Peng
中科院分区：
文献类型：
--
作者：
Gulfam, Raza;Orejon, Daniel;Zhang, Peng
在过去的十年里，由不变相材料(如Krytox GPL油)制备的光滑液体注入多孔表面(SLIPS)作为低附着力的工程功能表面得到了越来越多的研究。然而，相变材料(PCM)几乎没有被采用，尽管它们是潜在的候选材料，因为它们固有的润滑剂特性以及温度相关的相赋予独特的热响应可切换的润湿性。本文将石蜡(一种有机相变材料)应用于疏水的纳米多孔铜衬底上，通过旋涂和热处理的方法制备了相变SLIPS(PC-SLIPS)，克服了PC-SLIPS的局限性。这些PC-SLIPS的优点是促进了低附着力的Wenzel状态，而不是较早的在固相中完全钉扎的Wenzel状态和优化的滑态，而不是在液体中过量的PCM。此外，为了表征液滴与PC-SLIPSS的不同相之间的紧密相互作用，即固、泥和液三相，对接触线动力学进行了全面的研究，揭示了水滴的粘连和脱钉现象是温度响应性润湿态的函数。最后，还对PC-SLIPSS进行了水蒸气冷凝实验，证明了滴状冷凝的可行性以及液滴在固、液两相中尺寸分布的变化。结果表明，这种工程表面具有巨大的潜力，通过热响应可切换的润湿性来促进和调节滴状冷凝，用于热传递和水收集应用。
Slippery liquid-infused porous surfaces (SLIPSs) prepared with phase invariant materials (e.g., Krytox GPL oil) have been increasingly researched as low-adhesion engineered functional surfaces in the last decade. However, phase change materials (PCMs) have been scarcely adopted, although they are potential candidates because of their inherent lubricant characteristics as well as temperature-dependent phases empowering unique thermo-responsive switchable wettability. Here, paraffin wax (an organic PCM) has been applied on a hydrophobized nanoporous copper substrate to realize the phase-change SLIPSs (PC-SLIPSs) fabricated via spin-coating followed by thermal annealing, which overcomes earlier limitations encountered on the PC-SLIPSs. Advantages of these PC-SLIPSs are the prompting of a low-adhesion Wenzel state as opposed to the earlier completely pinned Wenzel state in the solid phase and the optimized slippery state without excess of PCM in the liquid phase. Further, in order to characterize the intimate interactions between liquid droplets and the different phases of the PC-SLIPSs, that is, solid, mush, and liquid phases, the contact line dynamics have been comprehensively investigated, unveiling the water droplet adhesion and depinning phenomenon as the function of the thermo-responsive wetting states. Lastly, the PC-SLIPSs have also been tested for water vapor condensation, demonstrating the feasibility of dropwise condensation and the shift of the droplet size distribution in both the solid and liquid phases. The results suggest that such engineered surfaces have great potential to prompt and tune dropwise condensation via thermo-responsive switchable wettability for heat transfer and water harvesting applications.