Preparation of Graphene Fibers

Graphene owns intriguing properties in electronic, thermal, and mechanic with unique two-dimension (2D) monolayer structure. The new member of carbon family has not only attracted great attentions in scientific research, but also showed great potential for many applications. Graphene sheets can self-assemble into macroscopic structures, which is conducive to further explore the value of graphene material in application, and also the future major trends. This dissertation introduces the preparation of graphene fiber by graphene oxide solution as spinning dope. The graphene oxide is selected to solve the poor wettability of graphene hindering its direct wet spinning. The oxygen-containing groups on graphene oxide surface make it hydrophilic. The graphene fibers were prepared in the following steps: Firstly assemble the graphene oxide into graphene oxide fibers by wet spinning; then turning the graphene oxide fibers into graphene fibers by thermal reduction. To observe the graphene oxide immersing in the coagulation bath at different times by SEM and the assembly mechanism of macroscopic graphene oxide fibers could be studied. In this work, the conductivity of the graphene fibers have been measured using the four-point method. Single mast mechanics test system was used for the tensile strength of graphene fibers. So the key process factors in graphene fibers preparation were explored and optimized, including the concentration of wet spinning dope, the composition of the coagulation bath, the change in diameter of the needles, injection rate and collection rate, etc. In summary, graphene oxide fibers were assembled by wet-spinning of the graphene oxide dope. And by the thermal reduction graphene fibers were prepared successfully. After studying the assembly mechanism of graphene fibers, the better raw materials and the more proper preparation conditions were chosen to make the fibers which have the superior performances.