Self-assembled free-standing graphene oxide fibers

It is a great challenge to directly assemble two-dimensional (2D) graphene oxide (GO) sheets into 1D fibers without any polymer or surfactant for their promising multifunctional applications. Herein, a facile self-assembly strategy is proposed to fabricate neat GO fibers from cost-efficient, aqueous GO suspension at a liquid/air interface based on the repulsive electrostatic forces, attractive van der Waals forces, and π-π stacking. During the self-assembly process and ultrasonic cleaning, the morphology variated from the source graphite powder through GO sheets to GO fibers and finally to neat GO fiber films. It is interesting to note that the electrical property of the GO fiber films was improved dramatically after subsequent low-temperature thermal annealing. The morphological evolution process and formation mechanism were analyzed on the basis of optical microscopy, scanning electron microscopy, and transmission electron microscopy observation, and the electrical characteristics was also discussion.