3D Printing of Flexible Strain Sensor Array Based on UV-Curable Multiwalled Carbon Nanotube/Elastomer Composite

Internet of things (IoT) is expected to significantly improve every aspect of society, especially in soft robotics, structural health monitoring, and human motion detection. Flexible strain sensors with high-performance characteristics as well as highly efficient and cost-effective maskless fabrication methods are the key components of IoT for these applications. Herein, a 3D printing technology using digital light processing is developed to fabricate high-performance flexible strain sensors based on UV-curable multiwalled carbon nanotubes/elastomer (MWCNT/EA) composite. The MWCNT/EA-based device with 2 wt% MWCNTs delivers a sensitivity of 8.939 with a linearity up to 45% strain. Additionally, the sensor has a detectable strain range from 0.01% to 60%, a high mechanical durability (10 000 cycles), and linear responses to humidity and temperature. Numerical simulation and impedance study indicate that the sensor works on the deformation-induced reduction of MWCNT conductive pathway. The developed device can be used to detect various external deformation, when combined with a near-field communication circuit. Moreover, a 4 x 4 strain sensor array is developed for sensing external stimuli distribution, further demonstrating the high performance of the 3D printed device.

Automated summary

The Internet of Things (IoT) is expected to significantly enhance various aspects of society, particularly in soft robotics, structural health monitoring, and human motion detection. This study developed a 3D printing technology to fabricate high-performance flexible strain sensors based on a multiwalled carbon nanotube/elastomer (MWCNT/EA) composite, demonstrating excellent sensitivity, linearity, detectable strain range, mechanical durability, and environmental responsiveness. Additionally, a strain sensor array was developed to further showcase the high performance of the 3D printed device in sensing external stimuli distribution.