Graphene nanoplatelet, multiwall carbon nanotube, and hybrid multiwall carbon nanotube–graphene nanoplatelet epoxy nanocomposites as strain sensing coatings

Abstract

Strain monitoring is of great interest in order to check components structural life, to prevent catastrophic failures, and, possibly, to predict residual life in case of unexpected events. In this study, strain sensing epoxy-based coatings containing carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and a mix of the two (MWCNT+GNP) have been produced, with the same initial electrical resistivity, and applied on glass fiber reinforced composites. Morphological, mechanical, and electrical tests have been then performed evaluating the resistance variation and the strain sensing performance of the sensors. A theoretical model to relate the resulting gauge factors to the different types of nanofillers has been applied. The results showed that all systems present a strain sensing performance with different gauge factors (and hence sensitivity) at low strain: GNP samples showed the highest gauge factor (10.3), MWCNT samples the lowest (1.5), and the mixed system lies in the middle (4.3). From analytical analysis, the value of initial distance among conductive particles was found to be 0.3 nm in the case of MWCNT and 1.2 nm for GNP, explaining why the gauge factors of the produced sensors are different.

Evaluating the X-ray-Shielding Performance of Graphene-Oxide-Coated Nanocomposite Fabric

“…It is important to note that the nanostructured materials can be produced and coated or painted practically, to conform to any shape of interest [22,[40][41][42]. Therefore, they can be applied when producing different radiation protection equipment, such as thyroid shields and protective aprons.…”

“…This will render possible a dual benefit of these materials. With the advancements in nanotechnology, the current trend is towards exploiting the properties of nanostructured material in order to create advanced nanocomposites for effective, lightweight, durable, radiation-resistant equipment [40][41][42].…”

Magnetic Self-Assembled Pearl Necklace-like Microstructure for Improving the Performance of a Flexible Strain Sensor

“…Such hybrid composites are more susceptible to tensile strain than those composed of CNTs alone. 30 In view of the serious agglomeration of nickel nanoparticles under a high magnetic field whose influence overpowered MWCNTs, the range of the curing magnetic induction intensity was chosen to be 0−0.75 T, which is far lower than previously reported cases. To explore the influence of the arrangement of the filled particles and MWCNTs on the resistance behavior, a theoretical model describing the resistance was established.…”

“…Repeated Loading−Unloading Cycle Properties. The comparison of strain range, sensitivity, and response time between PNS-C and a series of previously reported hybrid composites with similar components 6,12,17,[24][25][26]29,30,54,55 is shown in Figure 5c. Compared with most other composites, PNS-C has advantages in the effective strain range and sensitivity.…”

“…20−23 Particularly, flexible strain sensors based on hybrid composites have attracted wide attention because of the various fabrication methods and controllable filling materials that can effectively change their intrinsic properties. 1,24 Among them, significant progress has been made in relevant research studies of hybrid composites with carbon nanotubes (CNTs) and doped conductive particles, such as CS/MWCNTs-PDMS, 18 CNTs-PDMS, 3,25 CNT/Ti3C2Tx MXene-PDMS, 26 MWCNTs/CB-TPU, 27 MWCNTs-PU, 28 MWCNTs-PVA/PAA, 29 MWCNTs/graphene, 30,31 and SWCNT/rGO, 32 indicating that the synergistic effect between the backbone of carbon nanotubes and the filling particles results in these sensors being susceptible to tensile strain and having good comprehensive sensing performance. In addition, the sensing performance can be improved by modifying the structure of the material, such as peeled cheese, 16 serpentine pattern, 25 three-dimensional waves, 33 wrinkled, 34,35 origami sheet, 36 buckled structure, 37,38 cracked structure, 39 threedimensional (3D) network, 40 and nano-porous structure.…”