Preparation Graphene Via Redox And Surface Performance Of Its Films

Graphene has been paid much attention for its special two-dimensional structure and excellent electronic transport performance, mechanical strength, electron mobility, optical transparency. Researchers have a great number of studies on these fields, and have lots of excellent results, while less on the surface properties, relatively. So, the article has been originality researched the surface property of graphene films.Graphene was synthesized via chemical exfoliation of natural flake graphite following redox process. The characteristics of graphene were investigated by atomic force microscopy (AFM), high-resolution transmission electron microscope (HR-TEM) and Fourier transport infrared microscopy (FTIR). Results show that the graphene nanosheets are0.8nm height more or less, different layers, and C=O, C-O, O-H groups and defects on the surface of graphene.Subsequently, graphene films were fabricated via suction filtration method and measured via Optical Contact Angle Meter. Graphene films prepared via suction filtration show high hydrophobicity and high adhesion. The surface shows micro-and nanostructure. Irregularly stacked multilayer graphene nanosheets comprised the microstructure, whereas folding and agglomeration of graphene nanoflakes with few layers comprised the nanostructure. Then, the article researches the synthetic processes effect the surface contact angles (CA). The results are the CA gradually decreases with increased centrifugal speed ascribed to the variation in the microtextured surface morphology, and the graphene films fabricated via different organic dispersant show different hydrophobicity cased by different surface free energy.For researching the wetting of graphene film at different external environment, the graphene film were fabricated via spray coating on steel sheet, and measured its CA in corrosivity, electric field, annealing temperature and ultraviolet (UV) irradiation. Based on Wenzel’s theory and adsorption dynamics, an optimum mechanism is proposed for the surface wettability behavior.Then, to improve the surface property, CNTs were blended in graphene. The graphene/CNTs film shows higher hydrophobic, lower adhesive and high conductivity. The results of graphene and relevant mechanism could be useful for its application in the device and biomaterials application.