Silver Nanowires Eelectrodeposited from Reverse Hexagonal Liquid Crystals
- PDF / 2,043,172 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 86 Downloads / 217 Views
Silver Nanowires Eelectrodeposited from Reverse Hexagonal Liquid Crystals Limin Huang, Huanting Wang, Zhengbao Wang, Anupam Mitra, and Yushan Yan * Department of Chemical & Environmental Engineering University of California, Riverside, CA 92521, USA. * Tel: 909-787-2068; Fax: 909-787-2425; Email: [email protected]
ABSTRACT A novel, simple and efficient procedure was developed to electrodeposit one-dimensional Ag nanowires from reverse hexagonal liquid crystalline phases by using their one-dimensional cylindrical aqueous microdomains as space-confined reactors. Using this soft-template approach, flexible Ag nanowire arrays with wire diameter of 15-30 nm, high aspect ratio over 1000, and high wire densities over 1011 wires/cm2 were obtained. The Ag nanowire arrays can be easily collected by simply washing. The nanowires obtained can be used either in high-density bundle form or as single wires after dispersion by untrasonication. INTRODUCTION One-dimensional (1D) nanowires and nanowire arrays of metal, semiconductor and conductive polymer have attracted much attention because of their unique electrical, magnetic, optical, and mechanical properties and their potential application in nanodevices [1-5]. Although other successful approaches exist, the most widely used method for fabrication of nanowires and nanowire arrays remains to be electrodeposition guided by an appropriate porous “hard” template such as anodized alumina [1], track-etched polycarbonate and mica [1], carbon nanotube [6,7], zeolite/mesoporous silica [4,8,9], diblock copolymer [10]. Although the hard template approach has proved to be an effective route to metal, semiconductor, or polymer nanowires, most of the templates are tedious to fabricate and not easy to remove after wire deposition if needed. We are interested in developing a novel soft template approach that is simple, fast, and general by allowing fabrication of ultrahigh density nanowire arrays of a variety of materials including metal, semiconductor and conductive polymers. The method should also allow easy retrieval of nanowires by a simple washing process. Surfactant is a good candidate as such a soft template because surfactant molecules can self-organize to form a variety of supramolecular assemblies (micelles or liquid crystals) at different concentrations. Surfactant mesophase based synthesis of porous inorganic zeolite-like materials has been widely reported [11-13]. However, most of these preparations were carried out in low surfactant concentration (e.g., 0.1 M) where micelle formation or microemulsion dominates. By contrast, high surfactant concentration in oil phase results in reverse hexagonal liquid crystalline phase that is homogeneous and can supply 1D aqueous domains with high aspect ratio as space-confined growth environment for nanowires. This soft liquid-crystal template is advantageous in that its formation is fast, simple, and reproducible, and a great variety of organized assemblies are available by simply adjusting the liquid crystal composition. In this paper, we re
Data Loading...
