Soft CNT-Polymer Composites for High Pressure Sensors

Abstract

Carbon–polymer composite-based pressure sensors have many attractive features, including low cost, easy integration, and facile fabrication. Previous studies on carbon–polymer composite sensors focused on very high sensitivities for low pressure ranges (10 s of kPa), which saturate quickly at higher pressures and thus are ill-suited to measure the high pressure ranges found in various applications, including those in underwater (>1 atm, 101 kPa) and industrial environments. Current sensors designed for high pressure environments are often difficult to fabricate, expensive, and, similarly to their low-pressure counterparts, have a narrow sensing range. To address these issues, this work reports the design, synthesis, characterization, and analysis of high-pressure TPU-MWCNT based composite sensors, which detect pressures from 0.5 MPa (4.9 atm) to over 10 MPa (98.7 atm). In this study, the typical approach to improve sensitivity by increasing conductive additive concentration was found to decrease sensor performance at elevated pressures. It is shown that a better approach to elevated pressure sensitivity is to increase sensor response range by decreasing the MWCNT weight percentage, which improves sensing range and resolution. Such sensors can be useful for measuring high pressures in many industrial (e.g., manipulator feedback), automotive (e.g., damping elements, bushings), and underwater (e.g., depth sensors) applications.

Practical Considerations for Laser-Induced Graphene Pressure Sensors Used in Marine Applications

“…Further testing under hydrostatic pressure is needed to ensure LIG/PDMS composite sensors retain appropriate sensitivity over the pressure range. To reduce the compressive modulus, the PDMS curing agent weight percent can be further decreased, or other elastomers can be substituted (e.g., polymethyl methacrylate (PMMA) or thermoplastic polyurethane (TPU) previously proposed for marine depth sensors) [33,34]. LIGs for marine applications are also not limited to depth sensing.…”