title: From petal effect to lotus effect: a facile solution immersion process for the fabrication of super-hydrophobic surfaces with controlled adhesion.
abstract: In this paper, a convenient approach based on the reaction between an alkyl thiol and hierarchical structured Cu(OH)2 substrates is reported for the fabrication of super-hydrophobic surfaces with controlled adhesion. This reaction can etch the Cu(OH)2 microstructures and simultaneously introduce a coating with low surface energy. By simply controlling the reaction time or the chain length of the thiol, super-hydrophobic surfaces with controlled adhesion can be achieved, and the adhesive force between the surface and the water droplet can be adjusted from extreme low (∼14 μN) to very high (∼65 μN). The tunable effect of the adhesion is ascribed to the different wetting states for the droplet on the surface that results from the change of the morphology and microstructure scale after the thiolate reaction. Noticeably, the as-prepared surfaces are acid/alkali-resisting; the acidic and basic water droplets have similar contact angles and adhesive forces to that of the neutral water droplet. Moreover, we demonstrate a proof of water droplet transportation for application in droplet-based microreactors via our surfaces. We believe that the results reported here would be helpful for the further understanding of the effect of wetting states on the surface adhesion and the fabrication principle for a super-hydrophobic surface with controlled adhesion.
authors: Natural Science Research Center, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin, Heilongjiang 150090, P R China.
authors: Zhongjun
authors: Z
authors: Cheng
authors: Ming
authors: M
authors: Du
authors: Hua
authors: H
authors: Lai
authors: Naiqing
authors: N
authors: Zhang
authors: Kening
authors: K
authors: Sun
mesh_terms: D000269:Adhesives / Q000138:chemical synthesis* / Q000737:chemistry*; D000327:Adsorption; D003300:Copper / Q000737:chemistry*; D003460:Crystallization; D035264:Flowers; D057927:Hydrophobic and Hydrophilic Interactions; D006878:Hydroxides / Q000138:chemical synthesis / Q000737:chemistry*; D000070116:Lotus; D008855:Microscopy, Electron, Scanning; D055616:Microtechnology / Q000379:methods*; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry*; D017155:Wettability
chemical_list: D000269:Adhesives; D006878:Hydroxides; D012996:Solutions; C508959:copper hydroxide; D014867:Water; D003300:Copper