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Graphene fibers (GFs) are promising elements for flexible conductors and energy storage devices, while translating the extraordinary properties of individual graphene sheets into the macroscopically assembled 1D structures. We report that a small amount of water addition to the graphene oxide (GO) N-methyl-2-pyrrolidone (NMP) dispersion has significant influences on the mesophase structures and physical properties of wet-spun GFs. Notably, 2 wt % of water successfully hydrates GO flakes in NMP dope to form a stable graphene oxide liquid crystal (GOLC) phase. Furthermore, 4 wt % of water addition causes spontaneous planarization of wet-spun GFs. Motivated from these interesting findings, we develop highly electroconductive and mechanically strong flat GFs by introducing highly crystalline electrochemically exfoliated graphene (EG) in the wet-spinning of NMP-based GOLC fibers. The resultant high-performance hybrid GFs can be sewn on cloth, taking advantage of the mechanical robustness and high flexibility., A small amount of water can hydrate graphene oxide dispersed in organic solvents, resulting in formation of a liquid crystal phase and spontaneous rearrangement of graphene fibers in a flat geometry.

The wonder material, graphene, is now on the stage from academic research to real-world industrial application. Graphene oxide (GO), an oxygenated form of monolayer graphene platelet, is playing a crucial role for the large-scale production of minimal layer stacked graphene. Effective purification of GO by removing acidic and ionic impurities is the essential step for high dispersibility and long-term colloidal stability, endowing graphene oxide liquid crystal (GOLC) formation. GOLC can be readily utilized not only for the production of high quality graphene platelets but also in the straightforward design of multi-dimensional architectures, including 1D, 2D, and 3D, for the functional graphene-based material fabrication. Motivated from the inexpensive raw material and inherently scalable solution process, GOLC-based materials offer an idealized platform for the practical balance between material performance and economic cost. Herein, recent progress and future prospective associated with the commercialization of 2D GOLC-based materials are highlighted, specifically concerning the recent energy, environmental, and pandemic issues. Relevant crucial advantages and perspectives are reviewed for practical applications, including supercapcitors, membrane, molecular adsorption, and antimicrobial material.

Graphene is an emerging graphitic carbon materials, consisting of sp{sup 2} hybridized two dimensinal honeycomb structure. It has been widely studied to incorporate graphene with polymer to utilize unique property of graphene and reinforce electrical, mechanical and thermal property of polymer. In composite materials, orientation control of graphene significantly influences the property of composite. Until now, a few method has been developed for orientation control of graphene within polymer matrix. Here, we demonstrate facile fabrication of high aligned large graphene oxide (LGO) composites in polydimethylsiloxane (PDMS) matrix exploiting liquid crystallinity. Liquid crystalline aqueous dispersion of LGO is parallel oriented within flat confinement geometry. Freeze-drying of the aligned LGO dispersion and subsequent infiltration with PDMS produce highly aligned LGO/PDMS composites. Owing to the large shape anisotropy of LGO, liquid crystalline alignment occurred at low concentration of 2 mg/ml in aqueous dispersion, which leads to the 0.2 wt% LGO loaded composites. - Graphical abstract: Liquid crystalline LGO aqueous dispersions are spontaneous parallel aligned between geometric confinement for highly aligned LGO/polymer composite fabrication. - Highlights: • A simple fabrication method for highly aligned LGO/PDMS composites is proposed. • LGO aqueous dispersion shows nematic liquid crystalline phase at 0.8 mg/ml. • In nematic phase,more » LGO flakes are highly aligned by geometric confinement. • Infiltration of PDMS into freeze-dried LGO allows highly aligned LGO/PDMS composites.« less