Influence Of Mechanical Exfoliated Graphene On The Conductivity Property Of Graphene/Chitosan Film

With the continuous development of society, multifunctional materials have become increasingly demanded. Graphene has excellent conductivity, based on its unique properties, graphene and its composites have been widely applied in many fields, such as conductive filler, electrochemical sensors and so on.Chitosan has good biocompatibility and film-forming property, it was widely used in medicine and bioengineering. In this paper, the composite conductive films(graphene/chitosan composite films) with good conductivite and biocompatibility were prepared. The influence of the graphene morphology,surface state and adding amount on the graphene/chitosan composite films conductivity are studied.In this thesis, the graphenes(G1 and G2) were prepared by the ductile method, and the conductive graphene / chitosan composite films were prepared by adding graphene build conductive path. Composite films and reduction of graphene oxide/chitosan(RGO/CS) composite films were compared. Used the four-point probe method and multimeter method, we studied the conductivity of graphene/chitosan composite films with different graphene and graphene addition amount. Through the characterization methods such as TEM 、SEM 、XRD、FTIR 、 TG and Raman, we study the microstructure, the sheet size, the dispersion and surface states of RGO 、 G1 and G2. The mechanism of three different graphene’s effect on its composite films conductive performance was getted. The silver nanowire was prepared by the polyols hydrothermal method,and the silver nanowires(Ag NW) with high quality were prepared. The effect of adding the Ag NW and graphene on silver nanowires/graphene/chitosan composite films conductivity was studied.From Graphene/chitosan composite films conductivity detection, the volume resistivity was 286.74 Ω?m when the dosage of RGO in the RGO / CS composite films was 8 wt%, the G1/CS composite films in G1 adding amount was 6 wt%volume and resistivity was 81.25 Ω?m, the G2/CS composite films in G2 adding amount was 4 wt% and volume resistivity was 349.71 Ω?m. Under the same graphene content, conductivity of G2 / CS composite films > G1 / CS composite films > RGO/CS composite films. For getting the mechanism of different graphene on graphene/chitosan conductive films conductivity, the morphology layer size, dispersion and surface state of RGO, G1 and G2 are analyzed. The research shows that RGO is smaller pieces of layer thickness and size, while surface contains many defects lead to poor RGO/CS composite films conductivity. The conductivity of G1/CS and G2/CS is higher than the RGO/CS,this is due to the surface defects of G1, G2 prepared by mechanical stripping method is less than RGO. Contrasted the G1 / CS and G2 / CS composite films,we find that the conductivity of the G2 / CS composite films is better than the G1/ CS composite films, because the G2 slice thickness is lower than the G1, which make it easier to form conductive path in chitosan. However, the study of G1 /CS and G2 / CS composite films of graphene dispersion shows that the G1 is superior to the G2, because the G1 surface there are a few chitosan,which make it have better dispersion in the chitosan.The high-quality silver nanowires were prepared when the temperature at 160 ℃, hydrothermal time is 2.5 h, PVP /silver nitrate molar ratio of 3: 1 and PVP / Fe Cl3 dropping time of solution under30 min. We study the silver nanowires/graphene/chitosan composite films find when the amount of silver nanowires is low(2~10 wt%), the introduction of Ag NW will lead to the graphene conductive network was blocked, and enhance the level of graphene orientation degree, which leads to the composite films conductivity decreased, the law is significantly different from reported in literatures which add the high amount of silver nanowires.