Super‐Hydrophobic Surfaces: From Natural to ArtificialLibang Feng, Shuhui Li, Yuanxin Li et al.|Advanced Materials|2002 Abstract Super‐hydrophobic surfaces, with a water contact angle (CA) greater than 150°, have attracted much interest for both fundamental research and practical applications. Recent studies on lotus and rice leaves reveal that a super‐hydrophobic surface with both a large CA and small sliding angle (α) needs the cooperation of micro‐ and nanostructures, and the arrangement of the microstructures on this surface can influence the way a water droplet tends to move. These results from the natural world provide a guide for constructing artificial super‐hydrophobic surfaces and designing surfaces with controllable wettability. Accordingly, super‐hydrophobic surfaces of polymer nanofibers and differently patterned aligned carbon nanotube (ACNT) films have been fabricated.
Directional water collection on wetted spider silkReversible Super-hydrophobicity to Super-hydrophilicity Transition of Aligned ZnO Nanorod FilmsXinjian Feng, Lin Feng, Meihua Jin et al.|Journal of the American Chemical Society|2003 Remarkable surface wettability transition occurs with an inducement of ultraviolet (UV) for aligned ZnO nanorod films. The inorganic oxide films, which show super-hydrophobicity (left), become super-hydrophilic (right) when exposed to UV illumination. After the films are placed in the dark, the wettability evolves back to super-hydrophobicity. This reversible effect is ascribed to the cooperation of the surface photosensitivity and the aligned nanostructure. Such special property will greatly extend the applications of ZnO films.
Two-Dimensional Graphene Bridges Enhanced Photoinduced Charge Transport in Dye-Sensitized Solar CellsAs a novel two-dimensional (2D) material, graphene shows great benefits in electric and material science. Compared to 1D nanomaterials, it may show more excellent properties. Here, we introduced graphene as 2D bridges into the nanocrystalline electrodes of dye-sensitized solar cells, which brought a faster electron transport and a lower recombination, together with a higher light scattering. On the basis of these advantages, the short-circuit current density was increased by 45% without sacrificing the open-circuit voltage, and the total conversion efficiency was 6.97%, which was increased by 39%, comparing with the nanocrystalline titanium dioxide photoanode, and it was also much better than the 1D nanomaterial composite electrode.
Super-Hydrophobic Surface of Aligned Polyacrylonitrile NanofibersLin Feng, Shuhong Li, Huanjun Li et al.|Angewandte Chemie International Edition|2002 A water contact angle exceeding 170° is exhibited by the surface of aligned polyacrylonitrile (PAN) nanofibers without any surface treatment (the picture shows a cross-sectional view of the as-synthesized nanofibers). The nanofibers were obtained by simply extruding a PAN solution through an anodic alumina template into a solidifying solution. The factors that govern the hydrophobicity of aligned nanostructures are discussed.