title: Antifogging abilities of model nanotextures.
abstract: Nanometre-scale features with special shapes impart a broad spectrum of unique properties to the surface of insects. These properties are essential for the animal's survival, and include the low light reflectance of moth eyes, the oil repellency of springtail carapaces and the ultra-adhesive nature of palmtree bugs. Antireflective mosquito eyes and cicada wings are also known to exhibit some antifogging and self-cleaning properties. In all cases, the combination of small feature size and optimal shape provides exceptional surface properties. In this work, we investigate the underlying antifogging mechanism in model materials designed to mimic natural systems, and explain the importance of the texture's feature size and shape. While exposure to fog strongly compromises the water-repellency of hydrophobic structures, this failure can be minimized by scaling the texture down to nanosize. This undesired effect even becomes non-measurable if the hydrophobic surface consists of nanocones, which generate antifogging efficiency close to unity and water departure of droplets smaller than 2 μm.
authors.affiliation: Physique et Mécanique des Milieux Hétérogènes, UMR 7636 CNRS, ESPCI Paris, University Pierre and Marie Curie, University Denis Diderot, 75005 Paris, France.|LadHyX, UMR 7646 du CNRS, École polytechnique, 91128 Palaiseau, France.
authors.forename: Timothée
authors.identifier: 0000-0002-1166-1723
authors.initials: T
authors.lastname: Mouterde
authors.affiliation: Thales Research &Technology, Route Départementale 128, 91767 Palaiseau, France.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Lehoucq
authors.affiliation: Thales Research &Technology, Route Départementale 128, 91767 Palaiseau, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Xavier
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Antonio
authors.initials: A
authors.lastname: Checco
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Charles T
authors.identifier: 0000-0002-5157-0076
authors.initials: CT
authors.lastname: Black
authors.affiliation: Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Atikur
authors.identifier: 0000-0002-1275-7129
authors.initials: A
authors.lastname: Rahman
authors.affiliation: Thales Optronique SAS, 2 avenue Gay-Lussac, 78990 Élancourt, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Midavaine
authors.affiliation: Physique et Mécanique des Milieux Hétérogènes, UMR 7636 CNRS, ESPCI Paris, University Pierre and Marie Curie, University Denis Diderot, 75005 Paris, France.|LadHyX, UMR 7646 du CNRS, École polytechnique, 91128 Palaiseau, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Clanet
authors.affiliation: Physique et Mécanique des Milieux Hétérogènes, UMR 7636 CNRS, ESPCI Paris, University Pierre and Marie Curie, University Denis Diderot, 75005 Paris, France.|LadHyX, UMR 7646 du CNRS, École polytechnique, 91128 Palaiseau, France.
authors.forename: David
authors.initials: D
authors.lastname: Quéré