Mussel-inspired defect engineering enhances the mechanical strength of graphene fibers
demonstrated the mussel-inspired reinforcement of graphene fibers for the
improvement of different material properties. A research group under Professor
Sang Ouk Kim applied polydopamine as an effective infiltrate binder to achieve
high mechanical and electrical properties for graphene-based liquid crystalline
This bio-inspired defect
engineering is clearly distinguishable from previous attempts with insulating
binders and proposes great potential for versatile applications of flexible and
wearable devices as well as low-cost structural materials. The two-step defect
engineering addresses the intrinsic limitation of graphene fibers arising from
the folding and wrinkling of graphene layers during the fiber-spinning process.
fiber holds great promise for a wide range of applications, including flexible
electronics, multifunctional textiles, and wearable sensors. In 2009, the
research group discovered graphene oxide liquid crystals in aqueous media while
introducing an effective purification process to remove ionic impurities.
Graphene fibers, typically wet-spun from aqueous graphene oxide liquid crystal
dispersion, are expected to demonstrate superior thermal and electrical
conductivities as well as outstanding mechanical performance.
Nonetheless, owing to the
inherent formation of defects and voids caused by bending and wrinkling the
graphene oxide layer within graphene fibers, their mechanical strength and
electrical/thermal conductivities are still far below the desired ideal values.
Accordingly, finding an efficient method for constructing the densely packed
graphene fibers with strong interlayer interaction is a principal challenge.
Professor Kim’s team
focused on the adhesion properties of dopamine, a polymer developed with the
inspiration of the natural mussel, to solve the problem. This functional
polymer, which is studied in various fields, can increase the adhesion between
the graphene layers and prevent structural defects.
Professor Kim’s research
group succeeded in fabricating high-strength graphene liquid crystalline fibers
with controlled structural defects. They also fabricated fibers with improved
electrical conductivity through the post-carbonization process of polydopamine.
Based on the theory that dopamine
with subsequent high temperature annealing has a similar structure with that of
graphene, the team optimized dopamine polymerization conditions and solved the
inherent defect control problems of existing graphene fibers.
They also confirmed thatthe physical properties of dopamine are improved in terms of electricalconductivity due to the influence of nitrogen in dopamine molecules, withoutdamaging the conductivity, which is the fundamental limit of conventionalpolymers.
Teacher Kim, who drove the exploration, stated, “In spite of its innovative potential, carbon fiber utilizing graphene fluid gems still has constrains as far as its basic restrictions.” This innovation will be connected to composite fiber creation and different wearable material based application gadgets.” This work, in which Dr. In-Ho Kim took an interest as first creator was chosen as an intro page paper of Advanced Materials on October 4.