Stretchable Polyaniline@Epoxidized Natural Rubber Composites with Strong 3D Conductive Networks for High Performance Strain Sensors

Abstract

Flexible strain sensors are one of the core devices in wearable electronics. At present, it is still difficult to develop flexible strain sensors with high stretchability, sensitivity, and long-term stability. In this study, polyaniline (PANI) is successfully coated onto the surface of epoxidized natural rubber (ENR) nanospheres to form the PANI@ENR composites with core-shell structure by in situ polymerization. At PANI content of 5 wt% (PANI/ENR), the optimally conductive networks of PANI endow the composites with excellent comprehensive properties. The strain-sensing tests show that the PANI@ENR composites possess two successive linear sensing ranges (gauge factor of 7.3 in 0-400% strain, gauge factor of 1.8 in 400-1000% strain) and excellent cycling stability (over 2500 cycles at 0-50% strain). In addition, PANI@ENR-based strain sensors can monitor the movements of human finger joints, elbow joints, and knee joints in real time, indicating a wide range of potential applications in wearable flexible electronics.

Stretchable and Highly Sensitive Flexible Strain Sensor Based on a Three‐Layer Core–Shell Structure of Polydopamine/Polypyrrole@Natural Rubber for Human Activity Monitoring

“…[14][15][16][17][18][19] Typically, they are constructed using conductive sensing materials combined with elastomeric substrates, [11,20] such as polyurethane, [21,22] polydimethylsiloxane (PDMS), [16,23,24] natural rubber (NR), [25,26] and so on. The most commonly used strain sensing materials include carbon nanomaterials (carbon black, [24] carbon nanotubes, [27] and Mxene, [28,29] ), metal nanomaterials (silver nanowires [30] and silver nanoparticles [31] ), and intrinsic conducting polymers such as polyaniline (PANI), [32] polypyrrole (PPy), [33] and poly (3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT: PSS). [34] Excellent flexible strain sensors require a combination of a wide workable strain range and high sensitivity, which, in turn, necessitates high stretchability and a reliable sensing mechanism.…”

Multifunctional flexible strain sensor based on three‐dimensional core‐shell structures of silver nanoparticles/natural rubber

“…This is due to their exceptional flexibility, strain response characteristics, and capacity to convert mechanical signals generated by human motion into real-time electrical signals. [1][2][3][4] However, most flexible sensors do not have inherent antimicrobial and hydrophobic properties, which limits their use in human skin and healthcare industries. Therefore, it is essential to develop multifunctional sensors with outstanding flexibility, ductility, stable electrical conductivity, hydrophobicity, and antibacterial properties.…”

Fabrication and characterization of epoxidized natural rubber nanocomposites reinforced with mercapto‐functionalized nanozirconia filler

“…Furthermore, the unique properties of ENR have also led to the development of novel applications such as drug delivery systems and sensors. [34][35][36] The high polarity of ENR makes it an ideal candidate for encapsulating hydrophilic drugs, while its mechanical properties make it suitable for use in sensor applications. Overall, the ENR to produce ENR has opened up new possibilities for the development of advanced materials with superior properties, which have potential applications in various fields such as automotive, biomedical, and environmental industries.…”

“…ENR‐based scaffolds have shown excellent cell adhesion and proliferation, making them suitable for tissue regeneration and repair applications. Furthermore, the unique properties of ENR have also led to the development of novel applications such as drug delivery systems and sensors 34–36 . The high polarity of ENR makes it an ideal candidate for encapsulating hydrophilic drugs, while its mechanical properties make it suitable for use in sensor applications.…”