Piezoresistive properties for soft structures using hybrid CCB/CNT-based natural rubber latex composites
Rawiporn Promsung, Antonia Georgopoulou, Yeampon Nakaramontri, Ekwipoo Kalkornsurapranee, Frank Clemens
Abstract
This study explores the development of flexible sensors for soft structures. Conductive carbon black (CCB) and carbon nanotubes (CNT) were incorporated into a natural rubber (NR) matrix using glutaraldehyde (GA) as a curing system. The sensor properties of latex-NR composites with 20 phr of CCB, including variations of CNT content (0.5 to 3 phr), were examined. Increasing CNT content beyond 0.5 phr decreased tensile strength and elongation at break, but improved sensitivity and gauge factor (GF). Additionally, applying a voltage over 5 V caused a joule heating of the latex-NR composite strip elements. When integrated onto a soft tendon-based TPU bending actuator, higher CNT content reduced electrical signal drift during cyclic bending, enhancing long-term monitoring. This research highlights the potential of CCB/CNT-based latex-NR composites for soft structure applications, including soft robotics and health monitoring.