Microstructure-Controlled Polyacrylonitrile/Graphene Fibers over 1 Gigapascal Strength.

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Science

Background:

• Controlling microstructures like crystalline structures and microvoids is key for developing mechanically strong graphene fibers (GFs).
• Existing high-temperature graphitized GFs have limited ultimate mechanical strength due to structural defects such as imperfect crystallite alignment and micro-sized voids.

Purpose of the Study:

• To significantly enhance the mechanical strength of graphene fibers by controlling their microstructures.
• To explore the use of polyacrylonitrile (PAN) as a hybrid component in graphene oxide (GO) fiber fabrication.

Main Methods:

• Hybridizing graphene oxide (GO) dope solution with polyacrylonitrile (PAN).
• Controlling the fiber's inner structure orientation by applying tensile force at 800 °C.
• Utilizing the catalytic effect of graphene for directional carbonization of PAN between graphene sheets.

Main Results:

• Achieved hybrid graphene fibers (GFs) with a high strength of 1.10 GPa.
• Demonstrated successful microstructure control and enhanced mechanical properties without requiring graphitization at extremely high temperatures.
• Showcased PAN's role as a binder facilitating graphene sheet rearrangement and directional carbonization.

Conclusions:

• Controlling the alignment of the nanoassembled structure is an efficient strategy for achieving graphene's inherent performance in multidimensional structures like fibers.
• Hybridization with PAN and controlled processing offers a viable route to high-performance graphene fibers.
• The developed method provides a pathway to mechanically robust graphene fibers at potentially lower processing temperatures.