Highly conductive, flexible and functional multi-channel graphene microtube fabricated by electrospray deposition technique

Highly conductive and flexible graphene-based microtubes (μ-GTs) have many potential applications in catalyst supports and wearable electronics. However, there is a lack of effective method to fabricate the high-performance μ-GTs, especially the multi-channel ones. In this work, the electrostatic spray deposition technique was introduced to fabricate the graphene oxide-coated polyester thread from cost-efficient graphene oxide suspensions. After the polyester thread template was removed along with the reduction of graphene oxide by thermal annealing, the multi-channel μ-GT was prepared successfully. Due to the multiple structure of the cross section and the vertically aligned reduced graphene oxide sheets of the tube wall, the multi-channel μ-GT exhibits many excellent properties, such as highly conductive, good flexibility, and functionalization. For example, the electrical conductivity of the multi-channel μ-GT thermally reduced at 1200 °C is about 1.99 × 10⁴ S m⁻¹ at room temperature and can light a LED as a conductive wire. And the electrical conductivity is nearly invariable in either the straight or bent state though a cyclic bending test up to 800 times. In addition, the TiO₂/multi-channel μ-GT composite shows strong photocurrent response in which the multi-channel μ-GT provides a super platform due to the high specific surface area. The high-performance μ-GTs obtained by the simple method opens the immense potentials for application in wearable devices.