Researchers at Seoul National University of Science and Technology (SeoulTech) have developed a new approach to carbon-nanotube (CNT) sensors. The scientists’ invention could redefine wearable health monitoring. With vat photopolymerization (VPP), a technique where light selectively cures resin layer by layer, the team 3D printed highly stretchable and electrically conductive nanocomposites that proved to perform significantly better than previous materials.
“Our new CNT-nanocomposites are optimized specifically for VPP-based processes, allowing fabrication of highly complex 3D structures,” said Professor Keun Park, who led the study alongside Associate Professor Soonjae Pyo in the Department of Mechanical System Design Engineering.
Detailed in Composite Structures, the study explains how the researchers mixed multi-walled carbon nanotubes into an aliphatic urethane diacrylate (AUD) resin at concentrations from 0.1 to 0.9 weight percent. Having ensured even dispersion with an ultrasonic agitation, the team tested the inks for mechanical strength, conductivity, and print resolution. The winning formulation of 0.9 wt% CNT could stretch to 223 percent of its original length while still maintaining an impressive electrical conductivity and a fine printing resolution of 0.6 mm.
To demonstrate their invention’s real-world potential, scientists 3D printed triply periodic minimal surface (TPMS)-based piezoresistive sensors and integrated them into a smart insole that can track real-time foot-pressure distribution and movement.
“The developed smart-insole device demonstrates the potential of our CNT nanocomposites for 3D printing the next generation of highly stretchable and conductive materials,” said Prof. Pyo in a press release. “We believe these materials will be indispensable for wearable health monitors, flexible electronics, and smart textiles.”
