Self-Cleaning Efficiency of Artificial Superhydrophobic Surfaces
- 10 February 2009
- journal article
- Published by American Chemical Society (ACS) in Langmuir
- Vol. 25 (5), 3240-3248
- https://doi.org/10.1021/la803860d
Abstract
The hierarchical structured surface of the lotus (Nelumbo nucifera, Gaertn.) leaf provides a model for the development of biomimetic self-cleaning surfaces. On these water-repellent surfaces, water droplets move easily at a low inclination of the leaf and collect dirt particles adhering to the leaf surface. Flat hydrophilic and hydrophobic, nanostructured, microstructured, and hierarchical structured superhydrophobic surfaces were fabricated, and a systematic study of wettability and adhesion properties was carried out. The influence of contact angle hysteresis on self-cleaning by water droplets was studied at different tilt angles (TA) of the specimen surfaces (3° for Lotus wax, 10° for n-hexatriacontane, as well as 45° for both types of surfaces). At 3° and 10° TA, no surfaces were cleaned by moving water applied onto the surfaces with nearly zero kinetic energy, but most particles were removed from hierarchical structured surfaces, and a certain amount of particles were captured between the asperities of the micro- and hierarchical structured surfaces. After an increase of the TA to 45° (larger than the tilt angles of all structured surfaces), as usually used for industrial self-cleaning tests, all nanostructured surfaces were cleaned by water droplets moving over the surfaces followed by hierarchical and microstructures. Droplets applied onto the surfaces with some pressure removed particles residues and led to self-cleaning by a combination of sliding and rolling droplets. Geometrical scale effects were responsible for superior performance of nanostructured surfaces.Keywords
This publication has 30 references indexed in Scilit:
- Diversity of structure, morphology and wetting of plant surfacesSoft Matter, 2008
- Multiscale Dissipative Mechanisms and Hierarchical SurfacesPublished by Springer Science and Business Media LLC ,2008
- Chemistry and Crystal Growth of Plant Wax Tubules of Lotus (Nelumbo nucifera) and Nasturtium (Tropaeolum majus) Leaves on Technical SubstratesCrystal Growth & Design, 2006
- The Fine Structure of the Plant CuticlePublished by Wiley ,2006
- Classification and terminology of plant epicuticular waxesBotanical Journal of the Linnean Society, 1998
- Characterization and Distribution of Water-repellent, Self-cleaning Plant SurfacesAnnals of Botany, 1997
- Purity of the sacred lotus, or escape from contamination in biological surfacesPlanta, 1997
- Wettability and Contaminability of Insect Wings as a Function of Their Surface SculpturesActa Zoologica, 1996
- In vitro Reconstitution of Epicuticular Wax Crystals: Formation of Tubular Aggregates by Long‐Chain Secondary AlkanediolsBotanica Acta, 1995
- Epicuticular crystals of nonacosan-10-ol: In-vitro reconstitution and factors influencing crystal habitsPlanta, 1994