Summary of Research

My project here has focused on the fabrication and characterization of three dimensional (3D)
nanoscale metal or polymer mesh and metal sphere arrays. These 3D ordered arrays of nano
spheres and their replicas (porous networks) are of great interest for applications in a variety
of areas, including photonics, magnetics, thermoelectrics, catalysis, gas sensing and separations.

Using opal arrays (ordered silica nanospheres) as molds, metals or polymers can be infiltrated
into the void space between silica nanospheres. Subsequent dissolution of the opal produces
open three-dimensional metal or polymer mesh structures. Metal (such as nickel, cobalt, palladium,
and gold) and conducting polymer meshes are obtained by electrochemical deposition approach,
while the non-conducting polymer such as poly(methyl methacrylate) (PMMA) meshes are
prepared by chemical polymerization.

The nickel meshes can then be oxidized in the air to produce nickel oxide meshes. By the use of
poorly conducting nickel oxide mesh or PMMA mesh arrays as templates, well-defined metal
nanosphere arrays, such as those of nickel, gold and palladium, could be readily obtained by the
electrodeposition method.

The optical properties of Ni meshes, hydrogen adsorption properties of Pd meshes, and magnetic
properties of Ni meshes, Co meshes, NiO meshes, Ni sphere arrays, Co sphere arrays and
Ni spheres / NiO meshes composite have been investigated. Some interesting phenomena were
observed. The fabrication and characterization of other technologically important metal meshes and
sphere arrays or mesh / sphere composites are still underway.

In addition, I have also done some work on the fabrication of one dimensionally metallic nanowires
by electrodeposition using porous anodic alumina membrane as template.

Please visit my publications and electron microscopic images webpapges
to get more info on my work.