Reversible Superhydrophobic to Superhydrophilic Conversion of Ag@TiO₂ Composite Nanofiber Surfaces

Abstract

A new type of superhydrophobic material consisting of a surface with supported Ag@TiO(2) core-shell nanofibers has been prepared at low temperature by plasma-enhanced chemical vapor deposition (PECVD). The fibers are formed by an inner nanocrystalline silver thread which is covered by a TiO(2) overlayer. Water contact angles depend on the width of the fibers and on their surface concentration, reaching a maximum wetting angle close to 180 degrees for a surface concentration of approximately 15 fibers microm(-2) and a thickness of 200 nm. When irradiated with UV light, these surfaces become superhydrophilic (i.e., 0 degrees contact angle). The decrease rate of the contact angle depends on both the crystalline state of the titania and on the size of the individual TiO(2) domains covering the fibers. To the best of our knowledge, this is one of the few examples existing in the literature where a superhydrophobic surface transforms reversibly into a superhydrophilic one as an effect of light irradiation.

Supported plasma-made 1D heterostructures: perspectives and applications

“…Thus, former studies have shown that the Ag@TiO 2 nanofibre surfaces described in section 3 are superhydrophobic (water contact angles (WCA) higher than 150º) but can be converted in superhydophilic (water contact angles virtually 0º) by UV light irradiation [69]. Changes in WCAs when TiO 2 and other oxides are subjected to UV irradiation are generally attributed to reversible modifications in the surface hydroxylation state and/or the removal by photo-oxidation of surface carbonaceous species [70].…”

Fabrication of Mechanically Stable Superhydrophobic Aluminium Surface with Excellent Self-Cleaning and Anti-Fogging Properties

“…In recently, superhydrophobic surfaces (with water contact angle larger than 150° and sliding angle (SA) is smaller than 10°) have shown great interest due to the potential application in selfcleaning materials [3], antifogging surfaces [4], antireflective surfaces [5], microfluid manipulation [6] and so on. Many novel methods for the fabrication of super hydrophobic surfaces have been developed such as anodic oxidation [7,8], chemical deposition [9], chemical etching [10][11][12][13][14][15], chemical vapor deposition [16][17][18][19], colloidal self-assembly [20][21][22], electrospinning [23,24], sol-gel [25,26] and some others [27,28].…”

Superlyophilic Interfaces and Their Applications

“…[35,39,[87][88][89][90][91][92][93] Chemical vapor deposition can obtain SLPL interfaces by depositing a thin layer with chemical reactions. [94][95][96] Here, we review some common and typical fabrication methods to generate SLPL interfaces, as shown in Table 1.…”