title: Magnet-induced temporary superhydrophobic coatings from one-pot synthesized hydrophobic magnetic nanoparticles.
abstract: In this paper, we report on the production of superhydrophobic coatings on various substrates (e.g., glass slide, silicon wafer, aluminum foil, plastic film, nanofiber mat, textile fabrics) using hydrophobic magnetic nanoparticles and a magnet-assembly technique. Fe(3)O(4) magnetic nanoparticles functionalized with a thin layer of fluoroalkyl silica on the surface were synthesized by one-step coprecipitation of Fe(2+)/Fe(3+) under an alkaline condition in the presence of a fluorinated alkyl silane. Under a magnetic field, the magnetic nanoparticles can be easily deposited on any solid substrate to form a thin superhydrophobic coating with water contact angle as high as 172 degrees , and the surface superhydrophobicity showed very little dependence on the substrate type. The particulate coating showed reasonable durability because of strong aggregation effect of nanoparticles, but the coating layer can be removed (e.g., by ultrasonication) to restore the original surface feature of the substrates. By comparison, the thin particle layer deposited under no magnetic field showed much lower hydrophobicity. The main reason for magnet-induced superhydrophobic surfaces is the formation of nano- and microstructured surface features. Such a magnet-induced temporary superhydrophobic coating may have wide applications in electronic, biomedical, and defense-related areas.
authors.affiliation: Centre for Material and Fibre Innovation, Deakin University, Geelong, Victoria 3217, Australia.
authors.forename: Jian
authors.initials: J
authors.lastname: Fang
authors.forename: Hongxia
authors.initials: H
authors.lastname: Wang
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Xue
authors.forename: Xungai
authors.initials: X
authors.lastname: Wang
authors.forename: Tong
authors.initials: T
authors.lastname: Lin
mesh_terms: D004574:Electromagnetic Fields; D005290:Ferric Compounds / Q000737:chemistry* / Q000528:radiation effects*; D057927:Hydrophobic and Hydrophilic Interactions; D008280:Magnetics; D008422:Materials Testing; D053758:Nanoparticles / Q000737:chemistry* / Q000528:radiation effects* / Q000648:ultrastructure
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide