Superhydrophobic (synonymous words: ultrahydrophobic, super water repellent) surfaces are characterized by a high water contact angle (>150°) with a small difference between advancing and receding contact angle (hysteresis). Because of the minimized adhesion forces contacting water drops have an approximately spherical shape and roll off completely by a slight tilt of the surface. This behaviour is the result of the interplay between a low surface energy material and the surface roughness. This principle can also be found in biological systems. Examples are the wings of insects or the leafs of certain plants, such as the lotus plant.
We use different strategies to design superhydrophobic surfaces
- Plasma etching of poly(tetrafluoroethylene) (PTFE)
- Disordered sedimentation of hydrophobic core-shell particles
- Generation of a rough surface structure by anodic oxidation of aluminium with subsequent formation of a hydrophobic coating
- Water drop on a superhydrophobic aluminium surface
- SEM-image of a rough aluminium surface (anodization in sulfuric acid solution followed by silane modification)
- SEM-image of a disordered layer formed by core-shell particles (SiO2-particels with a diameter of 200 nm and a coating of a fluorosilane)
- SEM-image of a disordered layer formed by SiO2-particels with a diameter 200 nm with a shell of poly(styrene)
Research projects:
SMWK - research project :"Aluminiumwerkstoffe mit nachhaltiger ultrahydrophober Oberflächengestaltung"
BMBF - research project :" Erzeugung ultrahydrophober Aluminiumwerkstoffe"
Relevant publications
- Synytska, A.; Stamm, M.; Grundke, K.
Irregular fractal assemblies from 'Core-shell' particles - a way to design ultrahydrophobic surfaces more
Polymeric Materials: Science and Engineering 51 (2006) 194-195 - Thieme, M.; Frenzel, R.; Hein, V.; Worch, H.
Metal Surfaces with Ultrahydrophobic Properties: Perspectives for Corrosion Protection and Self-Cleaning more
Journal of Corrosion Science and Engineering : JCSE 6 (2004) 21 Seiten (http://www2.umist.ac.uk/corrosion/JCSE/ - Grundke, K.; Nitschke, M.; Minko, S.; Stamm, M.; Froeck, C.; Simon, F.; Uhlmann, St.; Pöschel, K.; Motornov, M.
Merging Two Concepts: Ultrahydrophobic Polymer Surfaces and Switchable Wettability more
VSP, Utrecht (2003) 267-291 - Frenzel, R.; Schmidt, S.; Hein, V.; Thieme, M.; Simon, F.
Verbundwerkstoffe
Ultrahydrophobe Aluminiumoxidoberflächen durch Texturierung und organische Beschichtungen more
Wiley-VCH (2003) 489-493 - Hennig, A.; Grundke, K.; Frenzel, R.; Stamm, M.
Ultrahydrophobic Surfaces: Relation between Roughness and Contact Angle Hysteresis more
Tenside Surfactants Detergents 39 (2002) 243-246 - Thieme, M.; Frenzel, R.; Schmidt, S.; Worch, H.; Simon,; Lunkwitz, K.
Generation of ultrahydrophobic properties of aluminium - A first step to self-cleaning transparently coated metal surfaces more
Advanced Engineering Materials 3 (2001) 691-695
