Ionic Liquid-Enhanced 3D Printed Flexible Resin for Pressure-Sensing Applications

Abstract

Iontronic materials show high performance for applications as pressure sensors due to the formation of the electric double layers (EDLs) at the dielectric/electrode interface. The properties of iontronic materials can be tuned, allowing the sensor to be customized for varied pressure ranges and ambient conditions. Furthermore, additive printing techniques enable to obtain customized cost-effective complex sensor designs, opening up new applications in the fields of medical devices, automotive systems, and consumer electronics. This work demonstrates the manufacturing process of a pressure sensor by stereolithography (SLA) 3D printing of a Liqcreate Flexible X resin in a gyroid framework, accounting for structural density variations. Furthermore, different concentrations (5 and 20% wt.) of the ionic liquid (IL) 1-butyl-3-methyl imidazolium thiocyanate ([Bmim][SCN]) are used to tune the EDL and maximize the sensor sensitivity. The capacitance response to applied pressure is analyzed across different designs. The configuration with 20% wt. IL content and lower quantity of pores exhibited superior performance, achieving a pressure sensitivity of 0.065 kPa−1 throughout a pressure range of 60 kPa. This study demonstrated the simple manufacturing process and ability to improve commercially available resins with ionic liquid, to achieve highly customized sensors.