Preparation Of Porous Anodic Aluminum Oxide Nano-template

In order to manipulate the morphology and property of porous anodic alumina (PAA), various PAA templates were fabricated by anodization in different types of electrolytes. The voltages in anodizing process were characterized by means of "Voltage-time"(V-t) curves. The surface and cross section of PAA templates were observed by SEM. The elements which composed the PAA templates were determined by EDX. The morphology and property were manipulated through changing anodization conditions. The stripping method was studied and the differences of wettability between six common solvents to different PAA templates were also investigated.First we compared differences of fabricated PAA templates between aqueous solution and non-aqueous(ethylene glycol, EG) solution in oxalic acid,sulfuric acid and phosphoric acid. Then we investigated the influence of non-aqueous solution on the morphology and property of PAA templates. The results show that the chemical reaction of sulfuric acid and ethylene glycol may cause the sharp-decrease of the sulfuric acid, so PAA templates only with some pits on surfaces are fabricated while without deeply-developed pores. Because of the weak connecting-force between cells, the prepared PAA templates with well-bounded cells are observed in oxalic acid ethylene glycol solutions. In phosphoric acid, compared to the PAA templates which are formed in aqueous solution, more ordered PAA templates with 180nm pore diameter are obtained in ethylene glycol solution, with which it is easy to assemble polymer nano-materials. Beacause of the high viscosity of ethylene glycol, the seriously released-heat of the solution led to the uneven reaction. Therefore, we produced PAA templates with large pore diameter in water and ethylene glycol mixed solvents. The results show that the ordering of PAA templates is improved significantly with the increasing of the ethylene glycol in mix solvents. It was the first times that, in phosphoric acid, the influences of different ratios of the water and ethylene glycol on PAA templates were discussed. Then in phosphoric acid with the optimum proportion of mixed solution of 50% water and 50% EG, the impacts of different voltages and temperatures on PAA templates were further studied. The results show that the ordering of PAA templates increases with the increasing of the voltage (below "breakdown"). The pore size is enlarged with the increasing of the temperature. At 200V, PAA templates with 200nm pore diameter are fabricated in mixed solution of 50% water and 50% EG at 5℃.On the basis of the traditional stripping method, we put forward "altered electrolytes stipping method", by which the through-hole PAA templates were obtained conveniently. It was proved to be an environment-friendly,safe and simple detachment method. In the end, we investigated the wettability of six common solvents to different PAA templates. The results show that for the same solevents, the wettability of PAA templates increases significantly with larger pore diameters while for the same PAA templates, the values of contact angle indicate that DMF spreads best by wetting the pore walls.