title: Monostable superrepellent materials.
abstract: Superrepellency is an extreme situation where liquids stay at the tops of rough surfaces, in the so-called Cassie state. Owing to the dramatic reduction of solid/liquid contact, such states lead to many applications, such as antifouling, droplet manipulation, hydrodynamic slip, and self-cleaning. However, superrepellency is often destroyed by impalement transitions triggered by environmental disturbances whereas inverse transitions are not observed without energy input. Here we show through controlled experiments the existence of a "monostable" region in the phase space of surface chemistry and roughness, where transitions from Cassie to (impaled) Wenzel states become spontaneously reversible. We establish the condition for observing monostability, which might guide further design and engineering of robust superrepellent materials.
authors.affiliation: Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.|Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China.
authors.forename: Yanshen
authors.initials: Y
authors.lastname: Li
authors.affiliation: Physique et Mécanique des Milieux Hétérogènes, UMR 7636 du CNRS, École Supérieure de Physique et Chimie Industrielles, 75005 Paris, France.
authors.forename: David
authors.initials: D
authors.lastname: Quéré
authors.affiliation: Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.|Institute for Nano- and Microfluidics, Center of Smart Interfaces, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
authors.forename: Cunjing
authors.initials: C
authors.lastname: Lv
authors.affiliation: Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China; zhengqs@tsinghua.edu.cn.|Center for Nano and Micro Mechanics, Tsinghua University, Beijing 100084, China.|Applied Mechanics Lab, Tsinghua University, Beijing 100084, China.|State Key Laboratory of Tribology, Tsinghua University, Beijing 100084, China.
authors.forename: Quanshui
authors.initials: Q
authors.lastname: Zheng
keywords: Cassie state; dewetting; interfaces; monostability; repellency