Strain‐sensing behavior of flexible polypropylene/poly(ethylene‐co‐octene)/multiwalled carbon nanotube nanocomposites under cyclic tensile deformation

Abstract

In this study, the associations between the structural evolution and physical properties of polypropylene/poly(ethylene-co-octene)/multiwalled carbon nanotube (PP/POE/MWCNTs) composites were established. The MWCNTs particles preferentially migrating from PP matrix to disperse in POE phase, which contributed to a richer network structure, thus resulting in a significant improvement for electrical conductivity, as well thermal stability, and toughness property with the elongation at break from 300% to 800%. Furthermore, the online strain-resistance analysis showed that introducing POE phase had a big advantage in improving the recovering resilience and stability of the conductive network structure of PP/POE/MWCNTs composites under a multitime circular tensile test with a strain of 5%. It was highlighted that the maximum and minimum electrical conductivity levels of PP/POE composites remained almost constant and even the ratio of the real-time resistance to the initial one was negative just at the beginning of each circulation regarding the strain stretching and recovery. This was attributed to the oriented conductive network structure of PP/POE nanocomposites induced by the applied strain, thereby increasing the electrical conductivity. Overall, this research provides a basic guidance for preparing composites with ultrahigh flexibility and stability under a circular deformation, which is an essential element taken into consideration for smart sensors with high sensitivity.

Modeling the resistive viscoelasticity of conductive polymer composites for sensor usage

“…A repeated resistance curve is a common way to characterize a strain sensor. 8,30 As shown in Fig. 9, the repeated resistance changes of the printed silver wire show shoulder phenomenon, 18 which is out of our discussion of this paper.…”

“…1–7 Conductive polymer composites (CPCs) are commonly used to fabricate soft resistive sensors due to their excellent mechanical properties, outstanding electrical performance, and low fabrication cost. 8 CPCs are usually prepared by adding conductive nanomaterials such as carbon-type nanoparticles (NPs), metallic NPs, or metal nanowires into the polymer matrix. 9 However, the CPCs usually contain viscoelastic ingredient materials, resulting in time-dependent effects, such as resistance relaxation, hysteresis, rate dependency, creep, and so on.…”

Synthesis and Characterization of Carbon Nanotube-Doped Thermoplastic Nanocomposites for the Additive Manufacturing of Self-Sensing Piezoresistive Materials

“…Subsequently, the average CNT distance reduces and the sample gains back some of its electrical conductivity due to these hysteretic effects. Although the reduction in stress is small (∼17%) between the 1st and 50th cycle, the stress during the 50th and 100th cycle is almost the same (a difference of ∼2.1%), showing that the mechanical performance of the nanocomposites is relatively stable 38 up to 100 repetitive stretch/ release cycles for an imposed strain of 5%. The instantaneous gauge factor during the 50th and 100th loading part of cyclic tests (see Figure 7b) relative to the first cycle indicates stable piezoresistive performance under constant amplitude cyclic loading.…”

Fabrication and characterization study of ultrathin multi‐walled carbon nanotubes/polydimethylsiloxane composite membranes for strain sensing application

“…Sensing membranes to be used in pressure sensors and/or strain gauges are subjected to repeated loading/unloading and the reliability of the membranes are important for practical applications. [50][51][52][53] In order to understand the performance of MWCNTs/PDMS membranes under these circumstances, repeated loading/unloading tests were performed and characterizations were made on the tested membranes. Stepwise cyclic stretching-releasing tests were performed to evaluate the stability of the MWCNTs/ PDMS composites with different MWCNTs and PDMS contents.…”