耐用,超薄和防聚合物刷涂层,用于高效的冷凝热传递
Shuai Li1, Cheuk Wing Edmond Lam2, Matteo Donati2
1Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
ACS applied materials & interfaces
|December 20, 2023
概括
研究人员为金属表面开发了一种超薄的疏水涂层,以改善传热. 这种耐用的聚二甲基 (PDMS) 涂层可以有效地进行滴滴凝结,优于传统方法,并具有自清洁性能.
科学领域:
- 材料科学 材料科学 材料科学
- 表面化学 表面化学
- 热传递是一种热传递.
背景情况:
- 金属热交换器遭受水友表面,导致低效的薄膜凝结.
- 开发耐用,薄的疏水涂层,以实现高效的滴水凝结,仍然是一个挑战.
研究的目的:
- 在金属表面上创建一个强大的,超薄的疏水涂层,以增强滴状凝结.
- 为了研究涂层在高超和蒸汽条件下的性能和耐用性.
主要方法:
- 应用非结构化,超薄 (∼6 nm) 聚二甲基 (PDMS) 刷在铜表面.
- 在高超和蒸汽下测试了涂层的性能,温度为111°C,3m·s-1.
主要成果:
- 达到持续的滴状凝结时间长达8小时.
- 与薄膜凝结相比,观察到的传热系数是5-7倍.
- 证明了自我清洁特性,并减少了99%的细菌附着.
结论:
- 开发的PDMS刷涂层提供了一个低成本,可扩展和无的解决方案,用于高效的滴水凝结.
- 涂层的灵活性确保了低降落滑动阻力和出色的化学稳定性.
- 这种技术在各种传热系统中具有广泛的应用.
更多相关视频
相关概念视频
Thermal Insulation in Masonry Walls
In hot, dry climates, the thermal mass of masonry walls can be beneficial, absorbing heat during the day and releasing it at night, thereby stabilizing indoor temperatures. However, in most other climates, additional insulation is necessary to enhance thermal resistance.
External insulation can be applied using an Exterior Insulation and Finish System (EIFS), which involves affixing panels of plastic foam to the wall and covering them with a polymeric stucco reinforced with glass fiber mesh.
External insulation can be applied using an Exterior Insulation and Finish System (EIFS), which involves affixing panels of plastic foam to the wall and covering them with a polymeric stucco reinforced with glass fiber mesh.
Masonry in Cold and Hot Weather Conditions
In cold weather, masonry construction requires specific precautions to ensure mortar does not freeze before curing, as this can significantly weaken its strength and watertightness. Mortar temperature should be maintained between 60°F and 80°F to support proper hydration and curing. Below 40°F, mortar water must be heated, but should not exceed 120°F as high temperatures can reduce mortar's compressive and bond strength.
Other key practices include keeping masonry units and sand dry and...
Other key practices include keeping masonry units and sand dry and...
Mass Concreting
Mass concreting refers to the process of placing large volumes of concrete, such as in gravity dams. The heat generated during the cement hydration process and differential cooling rates within the concrete mass can lead to a temperature gradient, which can result in thermal cracks in the concrete mass.
To reduce the risk of such cracking, the concrete mix may incorporate low-heat cement and pozzolans to reduce the temperature rise. Pre-cooled angular aggregates and water-reducing admixtures...
To reduce the risk of such cracking, the concrete mix may incorporate low-heat cement and pozzolans to reduce the temperature rise. Pre-cooled angular aggregates and water-reducing admixtures...
Cold Weather Concreting
When freshly poured concrete is exposed to freezing temperatures before it has set, the water within the concrete can freeze. This expansion disrupts the setting process, delays chemical reactions necessary for hardening, and increases the volume of pores within the hardened concrete, which weakens its overall structure. If the concrete manages to reach an appreciable strength before it freezes, the damage can be somewhat mitigated.
To counteract the negative impacts of cold weather, ensuring...
To counteract the negative impacts of cold weather, ensuring...
Frost Action on Concrete
Concrete structures in cold climates, such as those along roadsides, can retain moisture. This moisture makes them susceptible to frost-related damage when temperatures fall below freezing. Adding moisture worsens the damage during temperature fluctuations, leading to repeated freezing and thawing. De-icing salts, spread over these structures to melt ice, add to the freeze-thaw cycle, and draw even more moisture into the concrete.
This freeze-thaw cycle primarily causes surface scaling, where...
This freeze-thaw cycle primarily causes surface scaling, where...
Frost Resistant Concrete
Concrete's susceptibility to frost damage during freeze-thaw cycles demands strategic measures to enhance its frost resistance. Employing techniques like air entrainment, adjusting the water-cement ratio, proper curing, and selecting appropriate aggregates are essential.
Introducing microscopic air bubbles into the concrete mix through air entrainment creates small voids that accommodate ice expansion, thereby reducing internal pressures and preventing cracking. The optimal amount of entrained...
Introducing microscopic air bubbles into the concrete mix through air entrainment creates small voids that accommodate ice expansion, thereby reducing internal pressures and preventing cracking. The optimal amount of entrained...


