Polymer-based conductive nanocomposites are highly promising for use in wearable electronics and smart health monitoring. However, carbon nanotubes (CNTs) often agglomerate, making uniform dispersion difficult and limiting design freedom. Conventional methods restrict control over nanotube distribution and shape, while achieving both stretchability and conductivity has remained a persistent challenge. Researchers have now proposed CNT-based nanocomposites to facilitate 3D printing of highly stretchable and sensitive piezoresistive sensors that can be used to develop high-performance, wearable health monitoring devices.

A research team at Seoul National University of Science and Technology (Seoultech, Seoul, Republic of Korea) has developed carbon nanotube-based nanocomposites optimized for vat photopolymerization (VPP) 3D printing. By dispersing multi-walled carbon nanotubes into aliphatic urethane diacrylate resin, with concentrations between 0.1 and 0.9 weight%, they created inks suitable for additive manufacturing. Ultrasonic waves were used to ensure uniform dispersion, allowing fabrication of complex 3D structures with high accuracy.

The research team printed test specimens using these inks and analyzed their electrical, mechanical, and printing resolution properties. Results showed that the 0.9% CNT formulation achieved the best balance, stretching up to 223% of its length while maintaining conductivity of 1.64×10−3 S/m. The system reached a printing resolution of 0.6 mm, surpassing previously reported materials.

To demonstrate real-world application, the researchers used the optimized nanocomposite to print triply periodic minimal surface-based piezoresistive sensors. These sensors were integrated into a smart insole platform that monitored foot pressure distribution in real time. The findings, published in Composite Structures, show that the device successfully detected human movements and postures, highlighting its value for wearable health monitoring applications.

The technology’s potential goes beyond health monitoring. These CNT nanocomposites may also support the development of flexible electronics, soft robotics, and smart textiles. With further refinement, such materials could transform the future of wearable sensors and enable reliable, stretchable devices in multiple industries. The research team now plans to expand applications and strengthen performance in practical environments.

“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 Soonjae Pyo, co-lead author of the study. “We believe these materials will be indispensable for wearable health monitors, flexible electronics, and smart textiles.”

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