Clustered Ribbed-Nanoneedle Structured Copper Surfaces with High-Efficiency Dropwise Condensation Heat Transfer Performance

Abstract

We report that the dropwise condensation heat transfer (DCHT) effectiveness of copper surfaces can be dramatically enhanced by in situ grown clustered ribbed-nanoneedles. Combined experiments and theoretical analyses reveal that, due to the microscopically rugged and low-adhesive nature of building blocks, the nanosamples can not only realize high-density nucleation but constrain growing condensates into suspended microdrops via the self-transport and/or self-expansion mode for subsequently self-propelled jumping, powered by coalescence-released excess surface energy. Consequently, our nanosample exhibits over 125% enhancement in DCHT coefficient. This work helps develop advanced heat-transfer materials and devices for efficient thermal management and energy utilization.

Recent Progress in Bionic Condensate Microdrop Self‐Propelling Surfaces

“…In principle, any sub-microscale structures with a small feature size (tip size and interspace) and a certain height (or depth) can become effective candidates for creating CMDSP surfaces. In fact, except for arrays of closely packed nanotips, including nanocones, [22,27,50,69,70] nanoneedles, [21,28,31,66,71] nanopencils, [23] and tip-like nanotubes, [72,73] other architectures such as nano wires, [24,74] nanosheet arrays, [20,29,62,75] nanorod-capped nano pores, [68,76] the porous structure of nanoparticles, [67] nanoparticle aggregates, [73,[77][78][79][80] and two-tier structures [25,57,63,[81][82][83][84][85][86][87][88][89] have all been verified to be effective in endowing material surfaces with the desired CMDSP functionality as long as they follow these basic construction rules.…”

“…Similarly, various wetchemistry methods have been developed for the in situ growth of bionic CMDSP nanostructures on the surfaces of metal materials. [20][21][22][23][24][27][28][29]31,[66][67][68]70,[72][73][74][75][76]87] It is known that copper and aluminum are the most widely used metal materials, and the latest advances in their surface functionalization have shown remarkable potential in energy-related applications. Accordingly, we will briefly review recent progress in metal-based CMDSP surfaces.…”

“…Until now, much effort has been devoted to fabricating copper-based CMDSP surfaces consisting of various inorganic oxide nanostructures. [20][21][22][23][27][28][29]66,67,72,94] Inspired by nature, Qu et al [23] synthesized a type of Cu-based zinc oxide nanopencil array structure with CMDSP functionality, which was realized by diffusionlimited wet-chemistry crystal growth and silane modification (Figure 3a). Based on this, Luo et al [72] utilized zinc oxide nanopencils as a template and proposed a skillful preferential etching strategy to realize the controllable fabrication of [23] Copyright 2016, The Royal Society of Chemistry.…”

“…Efforts in the past decades have explored controllable fabrication, functionality, and performance optimization of bionic superhydrophobic surfaces with a contact angle above 150°, and they have resulted in technological innovations such as self-cleaning, drag-reduction, anticorrosion, antifogging, antifreezing and oil-water separation. [15][16][17][18][19] Recently, intensive www.advmat.de www.advancedsciencenews.com demonstration of their technological potential for enhancement of heat transfer, [20][21][22][23][24][25] energy saving, [26][27][28] and electrostatic energy harvesting. [29] Currently, this multidisciplinary research direction, which includes biology, chemistry, physics, materials science, and engineering, is still in its infancy, but it has exhibited significance and vigor in both fundamental and technological aspects.…”

“…Example applications are the enhancement of condensation heat transfer for high-efficiency thermal management and energy utilization, [20][21][22][23][24][25] energy-effective antifreezing for airconditioner heat exchangers and aircraft wings, [26][27][28] and electrostatic energy harvesting. [29] In general, condensate drops on typical flat hydrophobic surfaces are only shed off under gravity when their sizes are comparable to the capillary length (≈2.7 mm for water), [30] which creates undesirable effects such as large thermal resistance [20][21][22][23][24][25] and the freezing of subcooled drops. [26][27][28] Clearly, a great challenge is the timely removal of condensate drops at the microscale where the gravitational effect does not work.…”