title: Stimuli-responsive topological change of microstructured surfaces and the resultant variations of wetting properties.
abstract: It is now well established that topological microstructures play a key role in the physical properties of surfaces. Stimulus-induced variations of topological microstructure should therefore lead to a change in the physical properties of microstructured responsive surfaces. In this paper, we demonstrate that roughness changes alter the wetting properties of responsive organic surfaces. Oriented nematic liquid crystalline elastomers (LCEs) are used to construct the microstructured surfaces via a replica molding technique. The topological microstructure of the surfaces covered with micropillars changes with temperature, due to the reversible contraction of the LCE pillars along the long axis at the nematic-to-isotropic phase transition. This is directly observed for the first time under environmental scanning electron microscopy (E-SEM). A high boiling point liquid, glycerol, is used to continuously monitor the contact angle change with temperature. The glycerol contact angle of the microstructured surfaces covered with small pillars decreases from 118° at room temperature to 80° at 140 °C, corresponding to a transition from Cassie state to Wenzel state.
authors.affiliation: Institut Curie, Centre de Recherche, CNRS UMR 168, Université Pierre et Marie Curie, 26 rue d'Ulm 75248 Paris cedex 05, France. ziliang.wu@curie.fr
authors.forename: Zi Liang
authors.initials: ZL
authors.lastname: Wu
authors.forename: Renbo
authors.initials: R
authors.lastname: Wei
authors.forename: Axel
authors.initials: A
authors.lastname: Buguin
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Taulemesse
authors.forename: Nicolas
authors.initials: N
authors.lastname: Le Moigne
authors.forename: Anne
authors.initials: A
authors.lastname: Bergeret
authors.forename: Xiaogong
authors.initials: X
authors.lastname: Wang
authors.forename: Patrick
authors.initials: P
authors.lastname: Keller
mesh_terms: D032701:Biomimetics; D005990:Glycerol / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D050866:Liquid Crystals / Q000737:chemistry*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning / Q000379:methods; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D014867:Water; D005990:Glycerol