Carbon‐based conductive rubber composite for 3D printed flexible strain sensors

Abstract

Polymeric‐based flexible electronic devices are in high demand due to its wide range of applications. Natural rubber (NR) shows a great potential as matrix phase for flexible conductive polymer composites with its high elasticity and fatigue resistance. In this study, a new 3D printable conductive NR (CNR) composite was developed for strain sensor applications. Different contents of conductive carbon black (CCB) were mixed with NR latex to investigate the effect of the filler content on electrical and mechanical properties of the composites. The best‐known CNR composite with the CCB content of 12 phr was selected in order to produce the feedstock for the stereolithography process (SLA). The morphological, electrical, and mechanical properties of cast and 3D‐printed samples were investigated and compared. Although the 3D‐printed CNR sample had slightly lower conductivity than the cast one, it possessed comparable tensile strength and elongation at break, with values of 12.4 MPa and 703%, respectively. In addition, electrical responses of the CNR samples were investigated to demonstrate the electromechanical property of the material as a strain sensor. The 3D‐printed CNR sample exhibited the highest electromechanical sensitivity with a gauge factor (GF) of 361.4 (ε = 210%–300%) and showed good repeatability for 500 cycles. In conclusion, the development of this 3D printable functional material with great sensing capability will pave the way for innovative designs of personalized sensing textiles and other smart wearable devices.

Soft Wearable Piezoresistive Sensors Based on Natural Rubber Fabricated with a Customized Vat-Based Additive Manufacturing Process

“…A more interconnected network without accumulated AB areas was observed. This is in good agreement with the results reported by Srimongkol et al [ 50 ]. The black square-shaped particles in Figure 3 b were identified as the zinc oxide (ZnO), which was added to the NR latex during the pre-vulcanization process.…”

“…Developing composites that are compatible with additive manufacturing methods will enhance the use of functional NR composites in many fields of stretchable electronics, such as wearable motion sensors [ 49 ]. A printable conductive composite of NR was successfully developed using conductive carbon black as filler [ 50 ]. Its potential as a piezoresistive strain sensor was demonstrated, but piezoresistive performance, including signal drift and stress relaxation, was not yet investigated.…”