Shear-flow-induced graphene coating microfibers from microfluidic spinning.

The advancements in flexible electronics call for invention of fiber-based electronic systems by surface modification or encapsulation. Here we present novel shear-flow-induced graphene nanosheets coating microfibers by integrating the dip coating approach with the microfluidic spinning method. The core hydrogel microfiber was first spun continuously from the microfluidic device, and the shear flow from the dip coating approach allowed formation of the thin graphene oxide (GO) nanosheet coating shell. Because the fluid components and flow rates in the microfluidic spinning together with the lifting speed in the dip coating approach are highly controllable, the morphology of the resultant microfibers could be precisely tailored, including the core-shell structure, conductivity, and thermal responsibilities. These features equipped the resultant microfibers with the potential of thermal and motion sensors, and their value in gesture indicators has also been explored. Microfibers generated from such a simple and controllable method could be versatile in flexible electronics.