Preparation And Application Of Anodic Aluminum Oxide Template With Curved Surface

The anodic aluminum oxide(AAO)template as a template material has been widely used in the preparation of one or zero dimensional materials.The preparation of nanomaterials by template method is simple and easy to control.But the anodic alumina template used today are planar shape,template with curved surface has not been reported.The main work of this paper is as follows:AAO template was prepared by two-step anodization.And the effects of electrolyte,voltage and temperature on alumina template were analyzed.The four formation mechanisms of aluminum oxide template are analyzed in detail,such as field assisted dissolution model,field injection model,volume expansion model and so on.The curved alumina templates was prepared for the first time.The SEM was used to observe the formation of nanopores.And it is found that the highly ordered arrays of nanopores are formed on the surface of cylindrical and spherical templates.The scanning images of the cross section confirm that the formed nano cavities have no bending and bifurcation phenomena.The experiments found that the diameters of the inner and outer surfaces of the cylindrical template were 40 and 55 nm respectively,which indicated that the nano pores formed in the curved surface template were different from the straight holes in the planar template.It is a conical nanopore.These conical nanopores exhibit a radial arrangement,which is consistent with the normal vector of the cylinder and the sphere.The conical nanopore diameter and the change rate of diameter varied with the change of membrane curvature radius,and the nanopore diameter was 0.5 nm/?m(the film thickness is about 30 ?m).That is,by adjusting the radius of curvature,the diameter of the nano hole can be adjusted.However,this kind of adjustment can be realized only by changing the experimental conditions such as electrolyte concentration.The forming mechanism of curved surface is analyzed and discussed briefly.The conclusion is obtained that the tapered aperture is inversely proportional to the radius of the surface.That can be expressed as:At the end of this paper,the application prospect of surface template is prospected.And sandwich structure with porous layer-barrier layer-porous layer is formed on the curved surface of the template.The thickness of the barrier layer is very small,so that it will have some properties of the p-n junction.The growth of metallic nanowire arrays in curved template can be used to achieve sub-wavelength color magnification imaging.By increasing the number of stacked layers,the far field imaging can be achieved at least microns.This new type of template will be also widely used in optics,electronics and electrochemistry.