Planar interconnected graphene woven fabrics (GWFs) are prepared by a directly template-based chemical vapor deposition (CVD) method on Ni woven fabric templates under optimized growth parameters. Favourable catalytic performance of templates would be achieved after certain thermal annealing according to the increase in grain sizes and change of template crystalline structures; the number of graphene layers and the whole structure stability strongly depend on the concentrations of CH₄ and mesh densities of templates. With the exception of lightweight and high electrical conductivity, the GWF is simultaneously endowed with unique morphological features based on the continuous graphene structure.

Planar porous epoxy and GWF/epoxy composites are synthesized through a simple two-step proce...[ Read more ]

Planar interconnected graphene woven fabrics (GWFs) are prepared by a directly template-based chemical vapor deposition (CVD) method on Ni woven fabric templates under optimized growth parameters. Favourable catalytic performance of templates would be achieved after certain thermal annealing according to the increase in grain sizes and change of template crystalline structures; the number of graphene layers and the whole structure stability strongly depend on the concentrations of CH₄ and mesh densities of templates. With the exception of lightweight and high electrical conductivity, the GWF is simultaneously endowed with unique morphological features based on the continuous graphene structure.

Planar porous epoxy and GWF/epoxy composites are synthesized through a simple two-step process including impregnation epoxy resin on the Ni-WF and G/Ni-WF followed by etching out the Ni template. The composites have a porous structure with continuous flexible hollow graphene tubes (GTs) orthogonal interlaced in two perpendicular dimensions, therefore, the careful dispersion, surface functionalization and the arrangement of graphene nanosheets are avoided. Because of the incorporation of GWF, the GWF/epoxy composites present excellent electrical and mechanical properties: at 0.62 wt% graphene loading, the electrical conductivity of composites increases to 0.18 S/cm; the composites give rise to ~57% and ~67% higher fracture toughness at 0° and 45° directions; the tensile strengths of the composites with those two orientations are ~12% and ~16% higher than the one of solid epoxy. The effect of different orientations of hollow GTs is specifically investigated on mechanical properties and complicated fracture behaviour of the anisotropic composites. The in situ examination of the fracture process under the microscope indicates that the intriguing fracture behaviour taking place at the crack tip is caused by the blunting effect of the hollow GTs combining with the enhancement of graphene layers. It is found that the planar GWF may find favour for emerging demanding applications for porous composites.

A novel GWF/polydimethylsiloxane (PDMS) composite architecture is fabricated and works as a highly flexible and sensitive strain sensor that enables the detection of feeble human motions. Due to the distinctive functional features and reversible flexibility, the GWF/PDMS composites exhibit an extremely high piezoresistive gauge factor of 223 at a strain of 3% and excellent durability. The effects of growth condition and loading direction on their sensitivity are investigated to reveal the strain sensing mechanism. To bridge the technological gap between signal collection, processing and transmission in wearable strain sensors, a wireless wearable musical instrument prototype capable of converting human motions to music is developed for the first time by integrating the GWF/PDMS strain sensors with a smartphone via wireless Bluetooth communication. The demonstration not only offers insights into diverse applications of highly sensitive graphene-based composite sensors, but also opens new potentials of graphene composites to fabricate multifunctional devices for emerging areas, like healthcare and mobile electronics.

Freestanding PDMS-filled-GWF composites with ultra-stretchability and high structural stability are fabricated as an ideal sensing element in larger strain range applications. The composite sensors present unique sensing/switching behaviours depending on the level of external strains: a highly linear sensory capability below 10% with a gauge factor of 70, and a reversible sensing behaviour with a high gauge factor of 282 at 20%, followed by a reversible switching behaviour at larger deformations. By exploiting these sensing/switching capabilities of composites, a composite sensor to control the lighting of light emitting diodes (LEDs) and liquid crystal display (LCD) through alternating stretching or bending loads is successfully demonstrated. The innovative approach conceived for the first time here enable us to develop ultra-stretchable and highly stable GWF tubular structures with unique sensory/switching capabilities for multifunctional applications.