Preparation And Properties Of The Silk/Graphene Oxide Blended Functional Materials

Silk industry is an important support of national economy in China. Recently, silk is affected by reduction of farmland, shortage of labor, fierce competition and low added value of the products. Developing the versatile silk industry and increasing the added value of silk are the ways to achieve the transformation, upgrading and sustainable development of silk. In this paper, the silk is blended with graphene oxide(GO) to prepare the series of silk GO blended functional materials, and there provide a new research direction for silk materials. These functional materials will be applied to the areas of textiles, biomaterials and photoelectric materials. The research contents and results are as follows:(1) Preparation and structure of GO and r GO: GO and r GO are prepared successfully by means of Hummers method and HI reduced method. The results show that micro/nano scale of GO sheet is obtained with wrinkle and fold structure. The monolayer thickness of GO is about 0.8nm, and distance of the layer is 0.83 nm. Carbon element is composed of alkyl, aldehyde, carbonyl and carboxyl groups. After reduction by HI, the group of C=O disappears and the group of C-OH is also reduced. The intensity of sp2 in r GO is increased when compares to that of GO.(2) Preparation and properties of silk/GO blended functional fabric: The GO is successfully treated to the surface of silk fabric by means of dipping. Homogeneous distribution of GO on the surface of silk fabric is observed. The adhesion of GO on the silk fabric could be increased by means of ethanol. GO does not cause damage to the microstructure of the silk fibroin. However, there are hydrogen bonds between GO and silk fibroin. After treatment of GO, the UV blocking and antibacterial properties of silk fabric are increased. Furthermore, the UV blocking and antibacterial properties are increased with the increase of the concentration of treated GO.(3) Preparation and properties of the silk fibroin/GO blended porous three dimensional scaffold: The silk fibroin/GO three dimensional scaffold with porous structure is fabricated successfully by means of phase separation. After blending of GO, the silk fibroin scaffold also shows an irregular porous structure. However, the structure becomes compact. The results of SEM, EDS, FTIR and XRD investigate that the silk fibroin and GO blend uniformly, and the GO does not cause damage to the secondary structure of the silk fibroin. The breaking strength and young’ modulus of the silk fibroin/GO blended scaffold are higher than those of the pure silk fibroin scaffold. The result of MTT shows that the blending of GO contributes to the proliferation of osteoblast cells.(4) Preparation and properties of the silk fibroin/GO blended nanofibrous membrane: The silk fibroin/GO blended nanofibrous membrane is prepared successfully by means of electrospinning. GO sheet could disperse well in the silk fibroin/formic acid solvent system. Diameter of the blended nanofbers is thinner than that of the pure silk fibroin nanofibers. There are a large number of beads which packages the GO sheets on the surface of the blended nanofibrous membrane. There are hydrogen bonds between GO and silk fibroin. After blending of GO, antibacterial properties and biocompatibility of the silk fibroin nanofibrous membrane increase remarkably.(5) Preparation and properties of the silk fibroin/r GO blended membrane: Firstly, the GO solution is spin coated on the surface of silicon wafer. Secondly, the GO is reduced to r GO, and then the r GO is covered by silk fibroin. Finally, the silk fibroin/r GO film is peeled from the silicon wafer. The results show that prepared silk fibroin/r GO membrane is a transparent film with excellent transparency, flexibility and electrical conductivity.