Preparation Of Double-Sided Porous Anodic Aluminum(PAA)and Its Key Characteristics

With the rapid development of science and technology,nano-material have been exposed its unique values in various areas.Recent years,with the continued advancement and maturity in micro-nano technology,nano-material was playing an important role in research and daily life.Nano-sized materials,due to their superior structural characteristics,have great improvement of its performance not only in physical,chemical and other fields,but also in optical,biology,electromagnetism,etc.Porous Anodic Alumina(PAA)is a hexagonal close-packed nanopore array of porous materials with simple preparation process,low cost,wide application value,so that has a terrific application prospect.PAA has various advantages e.g.high aspect ratio,controllable dimension,high hardness and stability.It can be used as polymer,metal,metal oxide and other nano-materials filled template,and also can be used as a growth substrate for other nano-materials,so that to improve the capability of photoluminescence,electromagnetism and surface-enhanced raman scattering property,besides,it can be used in biomolecules,micro-nano-channels and sensors.In this paper,firstly,the properties,preparation methods and application of nano-materials are described.This paper introduces the research background and significance of nano-materials,expatiates on the present situation and the application value of PAA in domestic and abroad.This paper focuses on the process of PAA structural model and its growth mechanism,which is the theoretical basis for this study.Secondly,the oxalic acid was used as electrolyte for double-sided PAA preparation,through the growth process,current,oxidation time and other parameters was controlled.Based on the characterization of FE-SEM(Field Emission Scanning Electron Microscopy),the double-sided PAA with ideal morphology was grown.The TEM(Transmission Electron Microscope)sample preparation of double-sided PAA section was studied in detail,the internal structure was analyzed by means of TEM,HRTEM(High Resolution Transmission Electron Microscopy)and electron diffraction.Thirdly,the double-sided PAA was used to study the mechanism of its film removal.The changes of PAA morphology were observed by FE-SEM,and the morphological changes were observed in real time.It was found that the film removal process was carried out simultaneously in both axial and radial directions of PAA.When the film removal time is short,the process not be achieved,and when the film removal time is too long,the PAA itself will be destroyed.The mechanism of PAA film removal was systematically and the removal time of the best morphology was studied in order to shorten the removal process and increase PAA growth efficiency.Finally,the research on the pore-widening mechanism of PAA is studied.The real-time evolution of PAA morphology during the pore-widening process was observed by FE-SEM.Combining the theory of PAA's own multi-layer structure,systematic explains the mechanism of PAA pore-widening in the two parts of the surface and cross section,and achieve a different aperture size of the PAA controllable preparation.This research shows a certain significance and value of the applications in nano-template,nano-biology,nano-optics and sensors.