Boiling of highly wetting fluids is of great interest to thermal management of high-powered electronic devices, enhancement of which conventionally relies on functional modifications of surface shape and structure so as to promote bubble generation and growth. In this paper we attempt to combine the approach of porous texturing with a novel technique of surface wettability engineering to enhance saturated pool boiling of ethanol. Thin layers of microporous and nanoporous surface topographies were chemically deposited on an aluminum substrate by anodization in phosphoric acid and sulfuric acid, respectively. Boiling on the textured surfaces recorded over-twofold increases in terms of the heat transfer coefficient compared with that on a plain smooth surface, which can be attributed to a proliferation of active nucleation sites. The boiling incipience point on both porous surfaces, however, exhibited an interesting dependence on the initial wetting state of the surface. With the application of amphiphobic coatings of fluoropolymer modified with halloysite nanotubes, we managed to engender a biphilic (i.e., spatially alternating hydrophobicity and hydrophilicity) pattern on the porous-textured surfaces. The repeat control experiments on the hybrid surfaces showed an equally efficient mode of nucleate boiling, whose inception, by contrast, seemed to occur at consistently low superheats. The remarkable reduction (by more than 80%) of the minimum superheat at the boiling onset hints at an alternative nanobubble-related mechanism for heterogeneous bubble nucleation, which is notably less affected by incondensable gas, to the classic vapor-trapping-cavity model.

高润湿性流体的沸腾对高功率电子设备的热管理非常感兴趣，其增强通常依赖于表面形状和结构的功能修改，以促进气泡的产生和生长。在本文中，我们尝试将多孔纹理化方法与表面润湿性工程的新技术相结合，以增强乙醇的饱和池沸腾。通过分别在磷酸和硫酸中进行阳极氧化，将微孔和纳米孔表面形貌的薄层化学沉积在铝基板上。与普通光滑表面相比，纹理表面的沸腾传热系数增加了两倍以上，这可归因于活性成核位点的扩散。然而，两个多孔表面上的沸点都表现出对表面初始润湿状态的有趣依赖。通过应用埃洛石纳米管改性的含氟聚合物的两性涂层，我们成功地产生了多孔纹理表面上的双亲（即空间交替的疏水性和亲水性）图案。在混合表面上的重复控制实验显示出一种同样有效的核沸腾模式，相比之下，其开始似乎发生在始终较低的过热度下。沸腾开始时最小过热度的显着降低（超过 80%）暗示了与经典的蒸汽捕集腔模型相比，异质气泡成核的另一种纳米气泡相关机制，其受不可冷凝气体的影响显着较小。