title: Formation of superhydrophobic surfaces by biomimetic silicification and fluorination.
abstract: The amazing water repellency of many biological surfaces, exemplified by lotus leaves, has recently received a great deal of interest. These surfaces, called superhydrophobic surfaces, exhibit water contact angles larger than 150 degrees and a low contact angle hysteresis because of both their low surface energy and heterogeneously rough structures. In this paper, we suggest a biomimetic method, "biosilicification", for generating heterogeneously rough structures and fabricating superhydrophobic surfaces. The superhydrophobic surface was prepared by a combination of the formation of heterogeneously rough, nanosphere-like silica structures through biosilicification and the formation of self-assembled monolayers of fluorosilane on the surface. The resulting surface exhibited the water contact angle of 160.1 degrees and the very low water contact angle hysteresis of only 2.3 degrees, which are definite characteristics of superhydrophobic surfaces. The superhydrophobic property of our system probably resulted from the air trapped in the rough surface. The wetting behavior on the surface was in the heterogeneous regime, which was totally supported by Cassie-Baxter equation.
authors.affiliation: Department of Chemistry and School of Molecular Science (BK21), Center for Molecular Design and Synthesis, KAIST, Daejeon 305-701, Korea.
authors.forename: Woo Kyung
authors.initials: WK
authors.lastname: Cho
authors.forename: Sung Min
authors.initials: SM
authors.lastname: Kang
authors.forename: Dong Jin
authors.initials: DJ
authors.lastname: Kim
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Yang
authors.forename: Insung S
authors.initials: IS
authors.lastname: Choi
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D043942:Nanotubes; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D012821:Silanes; D012822:Silicon Dioxide; D005459:Fluorides