Graphene Oxide Paper (27056)
Novel graphene oxide paper material possessing unique structure with excellent mechanical properties and chemical tunability.
ADVANTAGE: Inexpensive paper-like material with superior physical properties compared to similar vermiculite, graphite foil and carbon nanotube materials.
SUMMARY: Inorganic “paper-like” materials based on exfoliated vermiculite or mica are employed as protective coatings, binders, dielectric barriers and gas-impermeable membranes. Graphite foils, composed of stacked expanded graphite platelets find use in packing and gasketing applications. Recently carbon nanotube bucky paper exhibiting mechanical and electrical properties suitable for fuel cell and composite applications have been reported. Herein a novel free standing membrane material prepared from graphene oxide (GO) with properties superior to the above materials is described. Membrane filtration of colloidal graphene oxide sheet dispersions and drying affords graphene oxide paper 1-30 µm thick. SEM and XRD analysis reveal well packed layers sandwiched between less densely packed 100-200 nm thick layers, with ~ 1 molecular water layer between sheets (Fig. 1).
Stress-strain curves of the material are similar to paper or foil like materials, however GO paper is very stiff as evidenced by clean fracture and 0.6% tensile strain (Fig. 2), comparable to flexible graphite (0.5%) and significantly lower than vermiculite (2.5%) and bucky paper (3-5.6%). The work of extension to fracture (350 kJ/m3) is comparable to bucky paper and 10 fold greater than flexible graphite. Tensile modulus of GO paper (32 GPa) is also significantly larger than reported for the other materials (Fig. 3). Cyclic loading measurements exhibit increased modulus of elasticity per cycle leading to better alignment of the plates and increased stiffness. Bending performance of graphene oxide paper show it to be a highly pliable macroscopic substance composed of stiff (in-plane) but compliant (out-of –plane) graphene oxide layers that are tightly interlocked providing high resiliency (Fig. 4 ).
Graphene oxide paper offers a material with enhanced properties compared with traditional carbon- and clay-based papers. Inexpensive graphene oxide promises a cost effective material for fabrication of large area sheets useful for membrane, anisotropic ionic conductors, supercapacitors and storage materials. GO paper may also serve as a carrier for polymers, ceramics and metals. The chemical functionality of the GO surface provides opportunities for chemical modification such as addition of crosslinkers to enhance interlayer attraction.
Rodney Ruoff, SonBinh Nguyen, Sasha Stankovich, Dmitriy Dikin
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