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Unidirectional water transfer effect from fabrics having a superhydrophobic-to-hydophilic gradient

journal contribution
posted on 2013-01-01, 00:00 authored by Hong Wang, Xungai Wang, Tong Lin
In this study, we demonstrate that fabrics having a wettability gradient from superhydrophobic to hydrophilic through the thickness direction show a novel directional water transfer effect: water can transfer from the superhydrophobic to the hydrophilic side, but not in the opposite direction unless an external force is applied. A sol–gel technology was used to prepare a nano-structured superhydrophobic coating on fabrics, and the coated fabrics showed water contact-angle as high as 165 degrees. When the coated fabric was subjected to a photochemistry treatment from one fabric side, the irradiated surface turned hydrophilic permanently, while the back side still maintained the superhydrophobicity. The treated fabric can transfer water droplet rapidly from hydrophobic to hydrophilic side, and the pressure allowing water breakthrough the fabric are different considerably between the two fabric sides. The directional water transfer effect is affected by the wettability gradient. Such a directional water transfer coating may be useful to develop new functional fabrics for defence applications.

History

Journal

Journal of nanoscience and nanotechnology

Volume

13

Issue

2

Pagination

839 - 842

Publisher

American Scientific Publishers

Location

Valencia, Calif.

ISSN

1533-4880

eISSN

1533-4899

Language

eng

Publication classification

C1 Refereed article in a scholarly journal

Copyright notice

2013, American Scientific Publishers