Key Laboratory of Bio-Based Material Science and Technology (Ministry of Education), College of Material Science and Engineering, Northeast Forestry University, Hexing Road 26, Harbin 150040, P. R. China.
State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
ACS Appl Mater Interfaces. 2020 Sep 9;12(36):40968-40978. doi: 10.1021/acsami.0c12504. Epub 2020 Aug 26.
Inspired by the distinct functions of desert beetles with efficient droplet nucleation and lotus leaves with excellent droplet removal, an integrated method is presented for the design of a superhydrophobic surface decorated with hydrophilic groups that can efficiently nucleate and remove water droplets. We constructed a cellulose-based superhydrophobic surface containing numerous olefin terminal groups by solvent exchange and spray coating. This surface is different from most of the reported biomimicking water harvesting surfaces that rely on complicated lithography and micropatterning techniques requiring special instruments. The obtained superhydrophobic surface was further modified using various thiol compounds via a thiol-ene reaction to manipulate the water harvesting property. The modified surfaces containing hydrophobic groups (e.g., 1-octadecanethiol and 1,1,2,2-perfluorodecanethiol) or a strong hydrophilic group (e.g., 3-mercaptopropionic acid and 6-mercapto-1-hexanol) exhibited insufficient fog collecting abilities due to poor water droplet nucleation or strong water adhesion. By contrast, the modified surface decorated with moderately hydrophilic amino groups combines the advantages of biological surfaces with distinct wetting features (such as fog-harvesting beetles and water-repellent lotus leaves), resulting in accelerated water nucleation and less compromise of the water removal efficiency. Molecular dynamic simulations revealed that the efficient droplet nucleation is attributed to the hydrophilic amino groups whereas the rapid droplet removal is due to the maintained superhydrophobicity of the amino group-modified surface. This strategy of decorating a superhydrophobic surface with moderately hydrophilic functional groups provides insight into the manipulation of droplet nucleation and removal for water collection efficiency.
受高效液滴成核的沙漠甲虫和具有优异液滴脱离性能的荷叶的启发，提出了一种集成方法，用于设计具有亲水性基团的超疏水表面，该表面可以高效地成核和去除液滴。我们通过溶剂交换和喷涂构建了一种含有大量烯烃末端基团的基于纤维素的超疏水表面。与大多数依赖于复杂的光刻和微图案化技术且需要特殊仪器的仿生集水表面不同，该表面具有不同的特性。通过硫醇-烯反应，进一步用各种硫醇化合物对获得的超疏水表面进行改性，以操纵集水性能。含有疏水性基团（例如，十八硫醇和全氟癸硫醇）或强亲水性基团（例如，巯基丙酸和 6-巯基-1-己醇）的改性表面由于液滴成核不良或强水附着力而表现出不足的雾收集能力。相比之下，用适度亲水性的氨基基团修饰的表面结合了具有明显润湿特性的生物表面的优点（例如，集雾甲虫和疏水荷叶），从而加速了水的成核，并且对水去除效率的影响较小。分子动力学模拟表明，有效的液滴成核归因于亲水性氨基基团，而快速的液滴去除则归因于氨基基团修饰表面保持的超疏水性。这种用适度亲水性官能团修饰超疏水表面的策略为控制液滴成核和去除以提高集水效率提供了思路。
