Preparation And Characterization Of Adhesive Material Based On PAA Template

Nature geckos can crawl freely on any surfaces. The adhesion and adhesion mechanism of foot structure have attracted more and more attentions. The strong adhesion force between gecko foot and object is derived from the unique structure of gecko foot. The thesis’ following studies focus on the fabrication of micro and nano array of biomimetic gecko foot.The paper firstly prepared the PAA templates by mild anodization method based on the mixed solution of phosphoric acid/oxalic acid as electrolytes. The effect of composition and concentration of electrolyte, oxidizing potential, oxidizing time and pore widening time on PAA template were discussed. Then, the PMMA and PS micro and nano arrays were fabricated by spin coating method in which single and double PAA as templates. The generation condition of polymer macro and nano array with different PAA pore size and different polymer concentrations were discussed. The surface topography of PAA and polymer array was characterized by SEM. The adhesion of macro and nano arrays was measured by AFM, and the contact angle to water was measured by contact angle test instrument.In terms of PAA template, the addition of oxalic acid in mixed solution could improve anodizing potential, which improved the regularity of PAA, significantly. And the PAA templates with continuous interpore distance from 300 to 500 nm were obtained. For a given electrolyte system, the thickness of PAA template has linear relationship with anodizing time, pore size increases with the increasing of pore widening time. The micro and nano arrays with best quality were obtained using 20wt% of PMMA/DMF solution and 25wt% of PS/DMF solution. For double layers polymer arrays, the thickness of small pore layer of double layers PAA template has an important impact on the polymer arrays. The surface of the polymer arrays will lodge and high adhesion occurs among them when the thickness of small pore layer is large. The macro and nano array structure of the polymer surface could increase the contact angle between polymer and water. Aspect of adhesion:the optimal adhesion of polymer was obtained in the condition of double layer polymer with surface nanopillar diameter of 65nm. The single nanopillar’s (diameter is 65nm) adhesion of double layers PMMA is 12.67Nn, the single nanopillar’s (diameter is 65nm) adhesion of double layers PS is 9.97nN. Obtained adhesive flexible polymer membrane would provide strong support for the fabrication of adhesive tape and bioelectrical dry electrode used by intelligent monitoring clothing.