3D printing of soft and porous composite pressure sensor with monotonic and positive resistance response

• Published in: Composites science and technology Vol. 241; p. 110126
• Main Authors: Tang, Zhen-Hua, Xue, Shan-Shan, Wang, De-Yang, Huang, Pei, Li, Yuan-Qing, Fu, Shao-Yun
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 18.08.2023
• Subjects: 3D printing; Carbon nanotube; Porous structure; Pressure sensor; Sensitivity; Carbon nanotube; Porous structure; Sensitivity; Pressure sensor; 3D printing
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2023.110126

Recently, 3D printing as a facile and customized technology has been employed to fabricate soft pressure sensors. However, the soft pressure sensors developed to date often suffer from nonmonotonic or negative resistance response, thus limiting their performance and applications. Herein, a new class of printable ternary inks with suitable rheological characteristics by the combination of conductive fillers (carbon nanotubes (CNTs)) and rheological modifiers (insulating microspheres) is developed unprecedentedly and enables the 3D printed composite pressure sensors with excellent mechanical elasticity and monotonic and positive resistance response. Firstly, the rheological behaviors of the as-prepared inks as well as relevant printing parameters are investigated in detail, and a printable phase diagram is proposed to select proper relevant printing parameters. Subsequently, the pressure sensing properties of the as-printed composite pressure sensor are demonstrated and it shows a monotonic and positive resistance response characteristic with a maximum gauge factor (GF) of 280 over a large range of 80% compression strain, exhibiting an outstanding balance between sensitivity and working range when compared with other previously printed pressure sensors. Furthermore, finite-element analysis (FEA) is conducted and a theoretical model for the resistance response is developed to clarify the response mechanisms of the as-printed pressure sensor. The excellent sensing performance suggests that the as-printed pressure sensor has great application potentials in the field of robotic perception and motion monitoring as demonstrated. [Display omitted]