冷凝液自输运纳米仿生表面研究

发布时间：2019-01-12 15:25

【摘要】：冷凝现象广泛存在于自然界和工业生产中,例如,发电、高效热能利用及热管理、海水淡化和环境治理等。然而,传统材料表面上冷凝液易滞留,会导致结冰结霜、材料导热性能大幅下降等问题。因此,近年来利用微纳加工技术开发新型冷凝液高效自输运表面已经引起科学界和产业界的高度关注,因为这种新型界面可用于开发新型功能材料,如抗结冰、抗结霜、湿气自清洁以及强化冷凝传热材料。本文受冷凝液自输运生物表面启发,开展了铜基纳米粒子多孔膜和超疏水-亲水杂化界面构筑的研究并表征了它们的冷凝微滴自输运性能。1)从冷凝微滴自驱离表面的基本设计原则出发:控制极低界面固-液黏附并同时控制亚微米结构间距避免湿气浸润,我们设计了一种具有冷凝微滴自输运功能的三维粗糙的纳米粒子多孔膜;提出基于协同“电化学参数择优控制氧化铈纳米粒子各向同性生长”与“析氢反应释放的微气泡作为造孔模板”的简易湿化学合成策略实现了氧化铈纳米粒子多孔膜在铜表面的原位生长。结果表明,相比于光滑疏水铜表面,合成的纳米样品具有小尺寸冷凝微滴自输运性能。2)我们提出巧妙利用超疏水表面上的冷凝微滴作为天然模板来引入小尺寸亲水微区的新型合成策略。这一合成策略协同利用了表面微滴的两个效应:一是作为离散的“粘合剂”来随机“捕获”撞击的聚乙烯醇(PVA)雾滴以实现小尺寸亲水微区的非均相修饰,二是使得融合微滴悬浮在纳米结构顶部,从而有效限制PVA与表面的接触面积并进一步控制了亲水微区的尺寸。随后,我们以超疏水氧化锌纳米铅笔阵列结构表面为例,验证了该合成策略的可行性。通过定量表征不同喷雾时间样品表面固-液界面黏附力,我们找到了优化的超疏水-亲水杂化冷凝界面。研究结果表明,相比于均质的超疏水表面,优化的杂化样品表面具有更高效的小尺度冷凝微滴自输运性能。基于仿生表面策略开发的纳米粒子多孔膜和超疏水-亲水杂化界面都具有小尺度冷凝微滴高效自输运性能,这为设计开发高效冷凝纳米表面提供了方向。
[Abstract]:Condensation is widespread in nature and industrial production, such as power generation, efficient thermal energy utilization and thermal management, seawater desalination and environmental control. However, the condensate on the surface of traditional materials is easy to stay, which will lead to freezing and frosting, and the thermal conductivity of materials will be greatly reduced. Therefore, in recent years, the development of new condensate self-transport surfaces using micro-nano processing technology has attracted great attention of the scientific and industrial communities, because this new interface can be used to develop new functional materials, such as anti-icing and anti-frosting. Moisture self-cleaning and enhanced condensation heat transfer materials. This paper is inspired by the self-transport biological surface of condensate. The surface self-transport properties of copper based nanoparticle porous film and superhydrophobic hydrophilic hybrid were studied and characterized. 1) based on the basic design principle of condensing micro-droplet self-driving surface: the control pole. Low interface solid-liquid adhesion and control of submicron structure spacing to avoid moisture infiltration, We have designed a three-dimensional coarse porous film with condensing micro-droplet self-transport function. A simple wet chemical synthesis strategy based on synergistic "electrochemical parameter preferential control for isotropic growth of cerium oxide nanoparticles" and "microbubble released by hydrogen evolution reaction as pore making template" was proposed to achieve multiple cerium oxide nanoparticles. In situ growth of pore film on copper surface. The results show that compared with smooth hydrophobic copper surface, The synthesized nanocrystalline samples have self-transport properties of small size condensing micro-droplets. 2) A new synthesis strategy is proposed to introduce small hydrophilic microregions by using condensing micro-droplets on superhydrophobic surfaces as natural templates. The synthesis strategy collaborates with two effects of surface droplets: one is to "capture" randomly the polyvinyl alcohol (PVA) droplets as a discrete "binder" to achieve heterogeneous modification of small hydrophilic microdomains. Second, the fusion droplets are suspended on the top of the nanostructure, which effectively limits the contact area between the PVA and the surface and further controls the size of the hydrophilic microregion. Then we take the surface of superhydrophobic zinc oxide nano-pencils as an example to verify the feasibility of the synthesis strategy. By quantitatively characterizing the adhesion between solid and liquid interface of different spray time samples, we have found the optimized superhydrophobic and hydrophilic hybrid condensation interface. The results show that compared with homogeneous superhydrophobic surface, the optimized hybrid sample surface has more efficient self-transport performance of small scale condensing micro-droplets. The porous film and superhydrophobic hydrophilic hybrid interface developed based on biomimetic surface strategy have high self-transport properties of small scale condensing micro-droplets, which provides a direction for the design and development of high-efficiency condensed nano-surfaces.
【学位授予单位】：上海大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB34

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