A highly flexible, electrically conductive, and mechanically robust graphene/epoxy composite film for its self‐damage detection

Abstract

Advanced functional composites have attracted a great attention for fabricating flexible devices. In this article, the GnP/epoxy composite film was prepared by mixing graphene platelets (GnPs) with epoxy through sonication process. The morphology, mechanical properties, and electrical conductivity of the prepared composites were investigated. As the GnP contents increased from 2.5 to 7.5 vol%, the composites showed an increase in strain sensitivity with the rapid decrease in the strain gauge to 4.4. Additionally, when dynamic movement of the flexible film was performed, at bending and twist angle of 135° and 180°, respectively, steady increase in both resistance changes were detected and compared. The electrical resistance of the flexible was measured over a temperature range of 20–95°C, an increase in temperature lead to a linearly equivalent increase in resistance. The composites can also detect slight pressure changes at 2 kPa compression force with rapid decrease of resistance. Additionally, fatigue test was performed with stable, sensitive, and no distinguishable reading under 2,000 stretching cycles. The composite film exhibits an excellent self‐sensing responds when fracture occurred. Thus, the obtained highly flexible, conductive, and mechanical robust composite sensor can be applied as advanced composites sensors for health monitoring.

Quantifying the Contributing Factors toward Signal Fatigue in Nanocomposite Strain Sensors

“…The first mechanism is quite straightforward, in that, as cycle number increases the electromechanical response will also increase in magnitude or undergo a positive drift due to crack initiation, transverse microcracking, and delamination caused by plastic deformation in the polymer matrix. 6,7 Ultimately this internalised cracking will result in the conductive filler network being artificially more sensitive to strain, resulting in the observed increase in electromechanical response with cycle number. [8][9][10][11][12][13] It is reported in CNT fibre nanocomposites that this change in composite resistance will increase linearly with cycle number and could allow for such materials to be applied as damage sensors.…”

Development of high thermally conductive and electrically insulated epoxy nanocomposites with high mechanical performance

“…The structural failure of nanocomposites is a complicated process, including the reduction of structural integrity in microscale. [32][33][34][35] The fracture morphology of CT specimen indicates important information for the toughening and fracture mechanisms of the composite, it was studied via SEM. The fractographs are shown in Figure 5.…”

Viscoelastic and mechanical characterization of graphene decorated with graphene quantum dots reinforced epoxy composites

“…From the SEM images of the fractured surfaces of the nanocomposites showed that the aminosilane improved the interfacial bonding. Meng, Q. et al 18 performed on epoxy composite films with GnP content of 7.5 vol% showed excellent tensile strength and Young's modulus. With Young's modulus peaked to 20 ± 1.8 MPa at 7.5 vol% of GnP content, while the tensile strength is recorded to be simultaneously increased to 1.2 ± 0.06 MPa.…”