High-strength graphene and polyacrylonitrile composite fiber enhanced by surface coating with polydopamine

Abstract

Carbon fibers are well-known reinforcing elements in advanced composites, but these materials remain expensive partly due to the complex processing methods used to form high strength and high modulus fibers. Graphene is seen as an alternative precursor for the formation of high strength carbon-based fibers. Here it is shown that the strength and modulus of graphene-based fibers are enhanced by incorporating a polyacrylonitrile (PAN) binder, surface coating with polydopamine (PDA) and through appropriate pyrolysis heat treatments. Fiber samples were prepared by a wet-spinning method such that the composition of liquidcrystalline graphene oxide (LCGO) and PAN could be varied over the full range. The maximum fiber mechanical strength (220 MPa) and modulus (19 GPa) occurred at a composition of LCGO (80 wt%) and PAN (20 wt%). The mechanical strength was further significantly increased to 526 MPa through pyrolysis of the LCGO/PAN fiber at 800 °C in a nitrogen atmosphere which caused carbonization of PAN. In addition, surface treatment of the LCGO/PAN fiber with PDA before carbonization improved the mechanical strength by an additional 40%.

Polydopamine Surface Chemistry: A Decade of Discovery

“…Several other recent reports have been published showing the ability of PD to enhance mechanical properties of composites. 249,250…”

Microstructure of fibres pressure-spun from polyacrylonitrile–graphene oxide composite mixtures

“…In recent years, there has been an increasing interest in graphene; as the specific surface area of graphene sheets is high owing to their single-layer morphology and two-dimensional nature. Graphene-based fibres have superior mechanical properties [1][2][3][4][5][6] . Reduced GO (rGO) fibres have recently been reported to be electrically and thermally conductive 7 , durable, flexible, and chemically resistant 8 .…”

Preparation and Evaluation of a Polyimide-Coated Ultrafine Gilt Molybdenum Wire and Its Knitted Mesh Used for Electromagnetic Reflectors

“…Compared to the uncoated gilt molybdenum wires, the PI-coated gilt molybdenum wires presented a higher broken force. The main reason for this was likely that the coating could help to heal the flaws and cracks on the gilt molybdenum wires to some extent [ 18 , 19 , 25 ]. Moreover, we can see from Figure 5 b that the initial moduli of the PI-coated gilt molybdenum wires were similar to those of the uncoated wires.…”