Preparation Of Shape-controllable Metal Nanowires Based On AAO Template-method

Nanodevices require a controllable fabrication of nanomaterials in shape, sizes and dimension. Among them, shape-controllable nanomaterial has caused more and more interests nowadays. In this paper, we prepared shape-controllable nanowires based on the porous anodic aluminum oxide (AAO) template. Application of the porous AAO template with different pore structure can obtain metal nanowires with different shapes (i.e. Y-branched, two-level branched, more complex tree-like nanostructures, as well as diameter-graded and periodic tree-bud nanostructures) by electrochemical deposition. Preliminary our research shows that some one-dimension nanomaterials can be shape-controllable.1)The porous Anodic aluminum oxide (AAO) templates with various branched pores were prepared through one- or multi-step varying the anodic voltage by a factor of 1 2 during an anodization of aluminum. The corresponding branched metal nanowires (i.e. Y-branched, two-level branched and more complex tree-like nanostructures) were achieved by electrodepositing metal into the branched pores of the porous AAO template. The stem and branches of the branched metal nanowires are single-crystalline. These branched metal nanowires can be made as function component of nanodevices and connect component ,which may be of great fundamental and practical significance.2)The porous AAO template with a graded pore diameter is obtained by changing the anodization voltage through a regular speed of 1.5V/min in sulfuric and oxalic acids. Based on the templates, several diameter-graded metal nanowires were achieved by electrochemical deposition. The porous AAO template with graded pore diameter ranging from about 12 to 31nm in sulfuric acids, corresponding the metal nanowires with gradient ranging from about 12 to 31nm; the porous AAO template with graded pore diameter ranging from about 11 to 55nm in oxalic acids, corresponding the metal nanowires have the same gradient change. These metal nanowires with single-crystalline structure may have some novel graded property in one-dimension direction, and thus be a new type gradient function material.3)The porous AAO template with periodic tree-bud nanostructures is made by fluctuating the anodization voltage between 39V and 41V periodically in oxalic acids. The corresponding periodic tree-bud metal nanowires were achieved by electrochemical deposition. The stem and"sporangium"of periodic tree-bud nanostructures nanowires are single-crystal. These one-dimension nanowires with periodic structure may be of novel periodic electricity and magnetism performance, gestating quite rich science connotation.