Flexible Multifunctional Sensors Using 3-D-Printed PEDOT:PSS Composites

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) has been recognized as a promising material for flexible sensor development, yet its fabrication often relies on traditional techniques such as dip coating, spin coating, inkjet printing, and lithography. Additionally, the role of additives in its multifunctional sensing capabilities remains largely unexplored. This study introduces 3-D printed, flexible, multifunctional sensors assembled using PEDOT:PSS-based composites. The effects of direct ink writing (DIW) parameters, particularly printing speed and pressure, on the electrical properties of the sensors, were investigated. The results showed that a pressure of 13 kPa and a speed of 4 mm/s yielded the most consistent electrical resistance. Moreover, the influence of dimethyl sulfoxide (DMSO) on the electrical, strain, and temperature sensing properties of the sensors was evaluated. Surface morphology analysis revealed an increase in surface roughness with the inclusion of DMSO, attributed to a microstructural rearrangement within the PEDOT:PSS composites. A multifunctional sensor based on PEDOT:PSS-based composites with simultaneous temperature and strain sensing capabilities was successfully demonstrated.