Graphene fiber (GF), a macroscopic one-dimensional assembly of individual graphene sheets, promises both extraordinary mechanical performance and superior multifunctionality. However, the properties of graphene fiber are still limited due to the unfavorable crystalline structures, especially induced by wrinkled conformations of graphene. A plasticization spinning strategy is presented to achieve GF with both high mechanical strength and electrical/ thermal conductivity. Adjusting the interlayer space from 1.2 to 1.8 nm by intercalating proper plasticizers to adjacent graphene oxide sheets enables graphene oxide fibers to achieve a 580% enhanced deformable plasticity. Such a plasticization spinning flattens random graphene wrinkles, and regulates sheets with high order and stacking density, thereby forming large crystallite domains. The GF exhibits all around record performance including mechanical strength (3.4 GPa), electrical conductivity (1.19 × 10 6 S m −1), and thermal conductivity (1480 W m −1 K −1). The optimally crystalline GF with the integration of benchmark overall properties and scalable fabrication is likely to be attractive and competitive in future industrial applications.

We establish a conformational phase map of 2D macromolecules in the experimental model of single-layer graphene oxide. The map covers predictable intramolecular phases and exotic intermolecular behaviors beyond theoretical predictions. The underling energy landscape reveals that the symmetry selectivity of phase transitions is rooted in the competition between elastic distortion and surface adhesion. Our map gives a clear understanding of the conformational transition of 2D macromolecules and initiates a unified framework to precisely control their multiscale condensed conformations.

Strength and toughness are usually exclusive in polymer nanocomposites with dispersed nanofillers. This intrinsic conflict has been relieved in a high filler loading range by mimicking the nacre structure of natural selection. However, at the low loading extreme, it still remains a great challenge. Here, we design a bicontinuous lamellar (BCL) structure to synergistically reinforce and toughen nanocomposites in the dilute range of nanofiller below 1 wt %. At a typical loading of 0.3 wt %, the BCL composite of graphene oxide (GO) and poly­(vinyl alcohol) (PVA) has an 8200% toughness and a comparably reinforced hardness of the dispersed counterpart, accompanying a 53-fold higher failure elongation that even exceeds that of pure PVA. Theoretical modeling and experimental analyses reveal that the continuous generation of massive crazes of GO layers endows the BCL composite with high toughness and surprising breakage elongation beyond those of pure PVA. The BCL organization is an alternatively optimal structure model to merge the exclusive strength and toughness together for damage-tolerant nanocomposites with a dilute range of nanofillers, other than nacre-like and well-dispersed structure, providing an alternative methodology to fabricate mechanically robust composites.

Achieving high spinning speed is critical to the production efficiency and viable application of fiber species. Graphene fiber (GF) has recently emerged as a carbonaceous fiber with excellent functionality. However, the extremely low wet spinning speed of GF has limited its applications. We realized high-speed blow spinning of neat GF and fabric by modulating the rheological properties of the graphene oxide (GO) dispersion. We achieved a speed of 556 m min–1, 2 orders of magnitude faster than that for wet spinning. We chose ultrahigh molecular weight polymers as transient additives to circumvent the intrinsic barrier effect of GO and achieve high spinning dope stretchability at low polymer percentagesdown to 25 wt %. Minimizing the polymer additive content ensures the high electrical/thermal conductivity of the blow-spun fiber and fabric. This work provides insight into the unique flow properties of 2D sheets and will promote the efficient production of graphene-based fibrous materials.

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