Authors Hohimer, C. J. ; Petrossian, G. ; Ameli, A. ; Mo, C. ; Pötschke, P.
Title 3D Printed conductive thermoplastic polyurethane/carbon nanotube composites for capactive and piezoresistive sensing in soft pneumatic actuators
Date 05.08.2020
Number 57959
Abstract With applications in flexible electronics and soft robotics, the ability to fabricate elastic functional materials with complex geometries has become highly desirable. In this work, flexible thermoplastic polyurethane/multiwalled carbon nanotube (TPU-MWCNT) composites were printed using multi-material fused filament fabrication (FFF) to study their feasibility towards built-in sensing capabilities in soft robotics. The microstructure, electrical conductivity, capacitive sensing, and piezoresistive sensing of the printed samples were investigated. MWCNT content, print orientation, and layer height was found to be the most influential parameters on the electrical properties while the nozzle and bed temperatures showed insignificant impacts. Overall, the in-line and through-line conductivities were one order of magnitude higher than the through-layer conductivity. Once the printing process was optimized, nanocomposites with 3 and 4·wt.%MWCNT showed repeatable and frequency independent conductivity behavior, reaching to a maximum value of 0.10 and 0.32·S/cm, respectively. A soft pneumatic actuator was then designed and printed out of TPU-MWCNT using the optimized process conditions. The built-in capacitive and piezoresistive sensing capabilities of the printed actuators were successfully demonstrated upon gripping contact and actuation at three different pressure levels. This work unveils the potential of integrating a variety of feedback sensors in robotic actuators through FFF process.
Publisher Additive Manufacturing
Citation Additive Manufacturing 34 (2020) 101281

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