Design, Simulation and Characterization of Flexible SWCNT Piezoresistive Sensors
Poornaiah Billa, K. Saujanya and Y. Srinivasa Rao
Flexible piezoresistive sensors are becoming increasingly popular for soft robotics, wearable electronics, and structural health monitoring because of their low processing costs, mechanical versatility, and light weight. Here, we present the creation and multiphysics simulation of a flexible piezoresistive sensor using screen-printed SWCNT ink on polymer substrates. To achieve controlled film thickness and good adhesion, the experimental work focuses on creating a uniform SWCNT(Single Walled Carbon Nanotube) ink and using a scalable screen-printing process to deposit it.
In addition to fabrication, a COMSOL Multiphysics model was created to examine the printed sensor’s electromechanical response to tensile loading. In order to investigate displacement, von Mises stress, relative resistance variation, and electric potential distribution, the model combines modules for solid mechanics and electric currents. Under 0–50% tensile strain, the screen-printed CNT resistors exhibited highly linear resistance–strain responses (R² = 0.998 for PI, 0.961 for PVC, and 0.968 for OHP) with the corresponding gauge factors at ε = 0.50 were 2.60 (PI), 0.85 (PVC), and 1.89 (OHP), consistent with the lower–mid range reported for printed CNT composites. Consistent with experimental trends, the simulation results demonstrate a linear resistance variation with strain and high gauge factor values. The electric potential plots shed light on charge transport throughout the printed film, while the stress distribution emphasizes the stability of the SWCNT film-substrate interface.
Keywords: Piezoresistive, strain sensor, screen printing, Carbon Nanotubes, resistivity