Hybridizing wood cellulose and graphene oxide toward high-performance fibers

Abstract

High-performance microfibers such as carbon fibers are widely used in aircraft and wind turbine blades. Well-aligned, strong microfibers prepared by hybridizing two-dimensional (2D) graphene oxide (GO) nanosheets and one-dimensional (1D) nanofibrillated cellulose (NFC) fibers are designed here for the first time and have the potential to supersede carbon fibers due to their low cost. These well-aligned hybrid microfibers are much stronger than microfibers composed of 1D NFC or 2D GO alone. Both the experimental results and molecular dynamics simulations reveal the synergistic effect between GO and NFC: the bonding between neighboring GO nanosheets is enhanced by NFC because the introduction of NFC provides the extra bonding options available between the nanosheets. In addition, 1D NFC fibers can act as 'lines' to 'weave and wrap' 2D nanosheets together. A 2D GO nanosheet can also bridge several 1D NFC fibers together, providing extra bonding sites between 1D NFC fibers over a long distance. The design rule investigated in this study can be universally applied to other structure designs where a synergistic effect is preferred. NPG Asia Materials (2015) 7, e150; doi:10.1038/am.2014.111; published online 9 January 2015 INTRODUCTIONStrong synthetic fibers such as carbon fibers have an important role in a range of applications from aircraft to wind turbine blades. However, these fibers are expensive and demonstrate limited performance. Nanofibrillated cellulose (NFC), derived mainly from wood, is an inexhaustible one-dimensional (1D) material with a diameter in nanoscale and a length in microscale. 1 This material has been explored as a possible building block for high-strength composites due to its impressive mechanical properties with an elastic modulus of~140 GPa. 2 Moreover, NFC possesses a high specific area and strong interacting surface hydroxyls, and can therefore act as an excellent reinforcement/binder. 3,4 In addition, chemically exfoliated twodimensional (2D) graphene oxide (GO) nanosheets exhibit excellent mechanical properties, a high aspect ratio and good processibility, making the nanosheets another attractive building block to produce strong microfibers. 5 Numerous hydroxyl, epoxide functional groups and carboxyl groups are present on the GO nanosheet basal planes and edges, providing strong bonding sites and allowing the GO nanosheets to be well-dispersed in water. 6 Transforming 2D GO nanosheets into strong and highly ordered microfibers is a promising feat. [7][8][9][10][11][12] Efforts have been made to improve the mechanical properties of GO-based microfibers by chemical cross-linking and polymer coatings as well as through giant GO nanosheets. [13][14][15][16] GO microfibers exhibiting a tensile strength of 442 MPa and an elastic modulus of 47 GPa have been

Anomalous scaling law of strength and toughness of cellulose nanopaper

“…The fundamental bottom-up strategy can essentially go beyond 1D building blocks (tubes, wires, filaments) toward 2D building blocks [e.g., atomic layers of graphene oxide (GO), boron nitride, and molybdenum disulfide] and 1D/2D hybrids. For example, it has been recently shown that hybrid microfibers containing well-aligned and mixed 2D GO sheets and 1D CNF fibers are both much stronger and tougher than the microfibers made of pure GO sheets or CNF fibers, due to synergistic enhancement of bonding between GO and CNF fibers (50). These fertile opportunities could lead toward a novel class of engineering materials that are both strong and tough with an array of potential applications, such as lightweight composites, flexible paper electronics, and energy devices.…”

Nanofibrillated cellulose/nanographite composite films

“…But they claimed that this value is much higher than those reported in other literature. Also Li et al (2015) combined graphene oxide (GO) nanosheets and nanofibrillated cellulose for use in high-performance device applications to replace traditional high-performance synthetic fibres, such as the carbon fibres used mostly in the aviation industry and in wind turbine blades. They reported that GO nanosheets have several hydroxyl, carboxyl, and epoxide functional groups on their basal plane and edges, strengthening the bonding in the material and giving the GO nanosheets good dispersion in water.…”

Cellulose‐Nanofiber‐Enabled 3D Printing of a Carbon‐Nanotube Microfiber Network

“…Then the gel fiber was pulled out and dried under tension at room temperature. The shear force introduced through extruding, and the tension applied during drying caused the building blocks to align along the fiber length direction, leading to a highly aligned microfiber . Good flexibility was demonstrated by making knots readily by hand, as shown in Figure b.…”

“…For comparison, we also simulate the sliding of the top and bottom CNT layers relative to the middle NFC layer in the CNT–NFC–CNT not aligned model. Recent studies on tensile failure of cellulose nanopaper (made of a network of NFC nanofibers) and cellulose–graphene oxide hybrid fiber reveal that, due to the facile formation nature of hydrogen bonds, the inter‐fiber sliding involves a cascade of events of forming, breaking, and reforming of hydrogen bonds in between neighboring NFC nanofibers. Each hydrogen bond breaking dissipates energy.…”