Construction And Application Of Several Micro/nano Composite Structured Materials Surfaces

The micro/nano composite structure on the materials surface can endow the materials with unique properties, such as superhydrophobicity, super-adhesion and super-light-absorbance et al, has comprehensive potential applications in the field of industry, military, medicine, aviation and so on. Surface enhanced Raman scattering (SERS) and superhydrophobic properties of materials surface are closely related to their micro/nano composite structures, so it is very essential to develop economic and efficient techniques for fabricating micro/nano composite structures on materials surface. We have fabricated the micro/nano composite structures on several materials surface by replicating template method and so on and researched their SERS and superhydrophobic properties. The main research contents, conclusions and original points of this thesis are summarized as following:1,We present an efficient, economic method for fabricating large-area silver nanobowl array structures via thermally evaporating silver onto the self-assembled monolayer of PS spheres. The materials for generating nanobowl array can be readily extended to a wide range and the size and period can be adjusted by varying the size of PS spheres. The test results of SEM indicate that the whole nanobowl array is composed of silver nanoparticles with average diameter size of ca.10 nm. The absorption peak of the optical absorption spectra at 410 nm indicate that surface plasmon resonance of silver nanoparticles exists on the nanobowl array. The silver nanobowl array was served as the reaction container and catalyst, the catalytic reduction reaction of p-nitroaniline by sodium borohydride was carried out inside the nanobowl arrays and the SERS spectra of the reactant and product molecules were measured. The results demonstrate that the nanobowl array is not only an excellent catalyst, but also an excellent SERS-active substrate. Silver nanobowl array is a multifunctional nanostructure, which can sever as reaction containers, catalyst and SERS-active substrate.2,We fabricated a large area flexible superhydrophobic polymer film with biomimic structure with an efficient and a low cost approach. In which, the photopolymer (NOA 63) was patterned into hemispheres array by twice-replicating from the self-assembled PS spheres array, and then silver were thermally evaporated onto the hemispheres array surface to achieve the hierarchical structures. The morphology of the prepared polymer surface of the polymer hemispheres/silver nanoparticles hierarchical composite structure is similar to that of the natural lotus leaf. After modifying the surface of silver nanoparticles with 1-Dodecanethiol, the biomimic film exhibits remarkable superhydrophobic property with a high water contact angle (CA) of about 166°and a low sliding angle (SA) of less than 3°. The wettability of the film surface can be adjusted by changing the thickness of silver film and the size of PS spheres. The biomimic polymer film exhibits good flexibility, which is expected to be applied in arbitrarily curved surfaces and can satisfy a wide range of applications.3,We present an approach to fabricate a stable flexible superhydrophobic polymer film. In which, the silver was thermally evaporated onto the templates of PS sphere monolayer, and then PVA aqueous solution was cast on it. After peeling off the glass substrate, removing the PS spheres in tetrahydrofuran solution, the films with silver microbowl array structures were obtained. The test results indicate the silver microbowl arrays were composed of silver nanoparticles with an average diameter size of ca.10 nm, so the polymer surface is a hierarchical microbowl/silver nanoparticles composite structures, which is helpful for obtaining surfaces with superhydrophobic ability. After modifying the silver surface with 1H,1H,2H,2H-perfluorodecanethiol, the polymer films exhibit remarkable superhydrophobicity with a high water CA of about 163°and a low SA of less than 3°. The silver nanoparticles stick firmly on the PVA substrate, which ensure the prepared films with excellent stability when being bended. This flexible superhydrophobic film may satisfy a wide range of applications, which is expected to be applied for self-cleaning of arbitrarily curved hydrophilic surfaces.4,We present an effective approach to change the surface of cellulose sheet from superhydrophilic to superhydrophobic by creating hierarchical micro/nano structures. The biodegradable superhydrophobic cellulose sheets are fabricated by the dissolution of cellulose, crystallization of cellulose gel, coagulation in acid and followed by the dip-coating of Teflon solution. Teflon nanoparticles were produced when the apolar Teflon solution was dip-coated on the polar cellulose sheet surface due to the difference of polarity, a biomimic surface with cellulose protuberances/Teflon nanoparticles composite hierarchical structure was obtained. Dip-coating Teflon solution on the surface can not only create a rough surface by producing the nanoparticles and the hierarchical micro/nano structures, but also reduced the cellulose sheet surface energy due to the incorporation of Teflon material with low-surface energy. The prepared cellulose sheets exhibit remarkable superhydrophobicity, satisfactory long-term chemical stability. Using this method, the cellulose materials can be fabricated into any desired forms, which will extend the potential applications of superhydrophobic cellulose products.