Planar Porous Graphene Woven Fabric/Epoxy Composites with Exceptional Electrical, Mechanical Properties, and Fracture Toughness

Planar
interconnected graphene woven fabrics (GWFs) are prepared
by template-based chemical vapor deposition and the GWFs are employed
as multifunctional filler for epoxy-based composites. Apart from flexibility,
transparency, lightweight, and high electrical conductivity, the GWFs
have unique morphological features consisting of orthogonally interweaved,
inherently percolated, hollow graphene tubes (GTs). The orthogonal
GT structure means that the GWF/epoxy composites hold significant
anisotropy in mechanical and fracture properties. The composites with
0.62 wt % graphene deliver a combination of excellent electrical and
fracture properties: e.g., an electrical conductivity of ∼0.18
S/cm; and fracture toughness of 1.67 and 1.78 MPa·m1/2 when loaded along the 0° and 45° directions relative to
the GT direction, respectively, equivalent to notable 57% and 67%
rises compared to the solid epoxy. Unique fracture processes in GWF/epoxy
composites are identified by in situ examinations, revealing crack
tip blunting that occurs when the crack impinges GTs, especially those
at 45° to the crack growth direction, as well as longitudinal
tearing of hollow GTs as the two major toughening mechanisms.