Preparation And Characterization Of Biomimetic Surface With Nanocone

The nanopattern on the surface of cicada wings can kill attached bacteria based solely on their physical surface structure at a high efficiency.This discovery has great potential in the field of bactericidal surface design.The structural parameters of nanocone are the most important,for example,the distance of nanocone is about 170 nm,and the higher aspect ratio,the higher efficiency.There are few methods for fabricating nanocones,some of which are time-consuming or too expensive,or the nanocone is in disorder.How to fabricate ordered nanocone arrays becomes a key problem.In view of the deficiencies of the traditional methods of fabricating nanocone arrays,the process of fabricating glass nanocone by glass fibre drawing technology was discussed in detail firstly in this thesis.All the experiment process is similar to the fabrication of optical fiber by rod-tube method.The experimental device is fiber-drawing tower,including feeding device,melting system and fixed length cutting system.The Schoot 8487 and 8330 should be chosen firstly since Schoot 8487 is an acid-resistant glass which is used as the core,while schoot 8330 that is used as tube is more etchable by HF.The two kinds of glasses have compatible thermal expansions to avoid excessive stress,and must have similar softening points so they can be drawn together.Secondly,under a certain drawing ratio,the drawing and bundle times must be strictly controlled to get orderly nanocone after etching by acid.On the other hand,the anodization method was adopted by combing nanoimprint lithography,to successfully fabricate nanocone arrays on the surface of PMMA,which is similar to cicada wing.The key of the experiment is the fabrication of porous anodic aluminum oxide(AAO)template with inverted conic holes.First,the nanopits on the Al surface was prepared by one-step hard anodizing(HA)process,which is most important.The nanopits can gather charge,which contribute a lot to the rapid growth of ordered AAO holes.Secondly,the inverted cone holes on the Al surface was fabricated by multi-step mild anodizing(MA)and pore-widening process.The distance of inverted cone is about 170 nm,which tallies with that of cicada wing.Lastly,the nanoimprint lithography was applied to copy the nanostructure of AAO to the PMMA surface,followed by etching the nanocone in the hot NaOH solution to increase its aspect ratio.