【作者】 章伟；

【导师】 邓旭；

【作者基本信息】 电子科技大学 ， 化学工程与技术， 2022， 硕士

【摘要】 超疏水材料在工业、军事、生物医学方面具有广阔的应用前景,然而传统微结构超疏水材料在高过冷度和高湿度环境下因发生冷凝而引起超疏水性能失效的问题正在成为超疏水材料投入实际应用的障碍,近年来超疏水材料的研究集中在提高油水分离效率、超疏液能力和机械稳定性上,对于超疏水抗冷凝失效能力的研究相对较少。本文提出了一种通过合理的表面设计来提高超疏水材料的抗冷凝失效性能的方法,并测试了所制备的超疏水材料在高过冷度和高湿度环境下的抗冷凝失效能力的强弱和持久性。具体研究工作如下:(1)本工作向纳米超疏水二氧化硅表面引入亲水硅基倒四棱锥微结构,通过耦合两种材料不同的导热率、表面能、固-液粘附力等性质获得了具有长效抗冷凝失效性能的铠甲化双亲表面。结合材料结构表征、表观接触角和滚动角的变化、粘附力的测量,通过对面积分数的设计,使水蒸汽在亲水微结构上的冷凝成核具有高度的选择性。本工作对铠甲化双亲表面的长效抗冷凝失效能力进行了实验观察,记录了冷凝液滴在超疏水表面上不断重复液滴成核-生长-合并-脱离-重新成核的现象。实验结果表明,该铠甲化双亲表面具有在室温25℃、相对湿度为70%、冷凝温度为1℃的条件下保持自身超疏水性能至少36 h的能力。(2)本工作制备了五种材料结构不同的超疏水表面(铠甲化双亲表面、超疏水光刻胶柱、超级干超疏水涂层、超疏水氢氧化铜纳米线和超疏水氧化铜纳米片),对它们分别进行了抗热液滴粘附能力测试、热液滴弹跳能力测试、热蒸汽实验和热液滴连续撞击实验。结合实验结果,可以获得不同超疏水表面在不同环境下抗冷凝失效的能力存在差异的原因,对分析材料的表面性质和结构尺度对抗冷凝失效能力的影响具有一定意义。实验表明,相对于其他几种超疏水表面,铠甲化双亲表面最具长效稳定抗冷凝失效的能力,证明了通过向纳米级超疏水表面引入连续亲水微结构的设计确实能保持超疏水状态在高湿度和高过冷度环境下的长期稳定,将导热、表面化学和固-液粘附等影响表界面性质的差异耦合到同一表面,实现冷凝成核的高度空间选择性可以作为一种解决超疏水表面因冷凝而发生超疏水性能失效问题的方案。更多还原

【Abstract】 Superhydrophobic materials have broad application prospects in industry,military,and biomedicine.However,the problem of superhydrophobic performance failure of traditional microstructure superhydrophobic materials due to condensation in high supercooling and high humidity environments is becoming the obstacle to practical application of the superhydrophobic materials.In recent years,research on superhydrophobic materials has focused on improving oil-water separation efficiency,super-liquid-repellent ability,and mechanical stability,and relatively little research has been done on super-hydrophobic anti-condensation failure ability.In this thesis,one kind of method to improve the anti-condensation performance of superhydrophobic materials through rational surface design is proposed,and the anti-condensation failure performance of the prepared superhydrophobic materials is tested under high subcooling and high humidity environments.The specific research work is summarized as follows:(1)In this thesis,a hydrophilic silicon-based inverted quadrangular pyramid microstructure was introduced into the surface of nano-superhydrophobic silica,and an armor with long-term anti-condensation failure performance was obtained by coupling different properties of materials such as thermal conductivity,surface energy,and solidliquid adhesion.the parental surface.Combined with material structure characterization,contact angle change,and adhesion measurement,the condensation and nucleation of water vapor on hydrophilic microstructures is highly selective through the design of the area fraction.The long-term anti-condensation failure ability of the armored amphiphilic surface was experimentally observed,and the phenomenon of continuous and repeated droplet nucleation-growth-merging-detachment-re-nucleation of condensed droplets on the superhydrophobic surface was recorded.The experimental results show that,The armored amphiphilic surface has the ability to maintain its own superhydrophobicity for at least 36 h at room temperature of 25 °C,relative humidity of70%,and condensation temperature of 1 °C.(2)In this thesis,five superhydrophobic surfaces with different material structures including the armored amphiphilic surface,superhydrophobic photoresist column,superhydrophobic super-dry coating,superhydrophobic copper hydroxide nanowires and superhydrophobic copper oxide nanosheets,and they were subjected to anti-heat droplet adhesion ability test,hot droplet bouncing ability test,hot steam test and hot droplet continuous impact test respectively.Combined with the experimental results,the reasons for the differences in the ability of different superhydrophobic surfaces to resist condensation failure in different environments can be obtained,which has certain significance for analyzing the influence of the surface properties and structural scales of materials on the ability to resist condensation failure.Compared with several other superhydrophobic surfaces,the experiments show that,the armored amphiphilic surface has the most long-term stability and resistance to condensation failure,which proves that the superhydrophobic state can indeed be maintained by the design of the continuous hydrophilic microstructure introduced into the nanoscale superhydrophobic surface.Long-term stability in high humidity and high subcooling environments,coupling differences in thermal conductivity,surface chemistry,and solid-liquid adhesion that affect surface-to-interface properties to the same surface to achieve high spatial selectivity for condensation nucleation can be used as a strategy to the problem of condensation failure on superhydrophobic surfaces.更多还原