Preparation And Wetting Property Of Diamond-based Nanocomposited Structure

In recent years, the hydrophobic (oleophobic) and hydrophilic (oleophohilic)materials are widely used in many fields, such as biological pharmacy, aircraft,shipbuilding, textiles, energy (solar), electrochemical and electrochemistry, etc.Diamond is material with unique excellent properties of superhard, chemical stability,high thermal conductivity and broadband gap semiconductor material, etc., one ofimportant features of diamond is wetting which closely related to diamond crystalorientation, surface energy and surface hydrogen (oxygen) terminated. The research ofdiamond wetting has an important value to promote its practical application. Designand production of new diamond composite structure and modulate its wetting is thecurrent important research topics in the field of diamond.This paper mainly includs: using chemical vapor deposition (CVD) method togrow diamond films, and depositing zinc oxide (ZnO) nanofilm on the polycrystallinediamond film; preparing nanometer diamond meshes; fabricatig cadmium sulfide(CdS) nanofilm/diamond mesh hybrid structure, and studying the correspondingwetting properties. The results are as follows:1. Depositing ZnO nano film on polishing or without polishing CVD diamond bymethod of magnetron sputtering, to improve the surface wetting of diamond film.When the substrate is not polished diamond (contact angle93°), ZnO/Diamondcontact angle is141°, and for polished diamond film (CA~87°), ZnO/Diamondcontact angle is98°. Experiments prove that the change of contact angle is closelyrelated with diamond film (polishing and without polishing) and nano ZnO filmroughness. The higher roughness, the higher contact angle. water droplets on theZnO/Diamond system for24hours, contact angle decreased from141°to34°, Afterhigh temperature (95oC), the contact angle recovery to141°, the system wetting isreversible.2. Diamond meshes having superhydrophobic (pH=1~14) and superoleophilic features were fabricated by coating chemical vapor deposited (CVD) nanocrystallinediamond film on copper mesh substrates. It is demonstrated that the hierarchicalmicro/nanostructures with the pore-induced capillary effect and the hydrogenatedsurface of diamond result in superhydrophobicity. The recyclability tests and theexamination of the stability of superhydrophobicity with the time scale taken in strongacid and basic solutions have been performed and they reveal that the diamondmeshes show excellent chemical inertness and a fairly reproduciblesuperhydrophobicity. diamond meshes are more favourable for exhibiting stablesuperhydrophobicity even with a large pore size (extending50μm to150μm). This canbe mainly attributed to the intrinsic superhardness of diamond film, which is rigid tosupport the liquid droplets stronger than any conventional materials.3. A highly efficient water–oil separation has been realized using these diamondmeshes. In addition, the superhydrophobicity and hydrophilicity of hydrogenated andoxidized surfaces of diamond meshes, respectively, are suitable for transferring waterpH droplets.4. Using hot filament CVD method preparation of boron doped p-type diamondmesh.Through continuous ion adsorption reaction method, growth n-CdS nano filmon the p-type diamond. Boron doped diamond film have hydrophobic properties,contact angle of87o, and CdS/diamond mesh of contact angle to107o.n-CdS/p-diamond mesh heterojunction used for decolorizing reaction of methylorange solution, prove its good photocatalytic performance.In summary, we studied the surface roughness of CVD diamond film, ZnO filmdeposition to improve the effect of diamond film hydrophobic. Micro-nano structureof diamond film was prepared, obtained the superhydrophobic and superoleophylic,can be used for high efficiency oil-water separation, and has stable in acid alkali. n-type CdS nano film growing on boron doped p-type diamond film, can achieve goodphotocatalytic properties. Mentioned in the present paper discusses the diamond baseof new type of composite structure and excellent properties of wetting, may find newphenomenon and working mechanism, is expected to develop diamond related newmulti-function devices.