3D-printed carbon nanotube sensors present potential for sensible well being monitoring

Polymer-based conductive nanocomposites, significantly these incorporating carbon nanotubes, are extremely promising for the event of versatile electronics, delicate robotics and wearable gadgets. Nevertheless, CNTs are troublesome to work with as they have an inclination to agglomerate, making it laborious to acquire a uniform dispersion. Furthermore, standard strategies restrict management over CNT distribution and form.

To beat these challenges, researchers are turning to additive manufacturing (AM) or 3D printing strategies, reminiscent of vat photopolymerization (VPP), which supply wonderful design freedom with excessive printing accuracy.

On this methodology, a light-weight is used to selectively remedy and harden layers of an ink inside a vat, step by step constructing a 3D object. Regardless of its benefits, it additionally poses a number of challenges. The presence of CNTs impacts the printability and curing properties of the inks. Furthermore, concurrently attaining excessive stretchability and electrical conductivity is a significant problem.

Now, a analysis staff led by Professor Keun Park and Affiliate Professor Soonjae Pyo from the Division of Mechanical System Design Engineering at Seoul Nationwide College of Science and Expertise in Korea has efficiently fabricated extremely stretchable, electrically conductive CNT-nanocomposites, utilizing VPP-type 3D printing.

“Our new CNT-nanocomposites are optimized particularly for VPP-based processes, permitting fabrication of extremely advanced 3D constructions,” explains Prof. Park. “We additionally used these supplies to additively manufacture new piezoresistive sensors and built-in them right into a wearable well being monitoring system.”

Their examine is revealed within the journal Composite Constructions.

The staff first ready polymer nanocomposite inks by uniformly dispersing multi-walled carbon nanotubes (MWCNTs) into an aliphatic urethane diacrylate (AUD) resin, with concentrations starting from 0.1 to 0.9 weight%. To attain uniform dispersion, they agitated the combination utilizing ultrasonic waves. The ready inks had been then analyzed to find out the optimum printing situations.

Subsequent, the staff additively manufactured check specimens utilizing the assorted inks and examined them for his or her mechanical and electrical properties, in addition to printing decision (the minimal thickness that may be printed). Outcomes confirmed that the formulation with 0.9 weight% CNT supplied the most effective stability of properties.

It might stretch as much as 223% of its authentic size earlier than breaking, whereas nonetheless attaining a outstanding electrical conductivity of 1.64 ×10⁻³ S/m, surpassing that of beforehand reported supplies. It additionally achieved a printing decision of 0.6 mm.

To exhibit sensible applicability, the researchers used the optimized CNT nanocomposite to 3D print versatile triply periodic minimal floor (TPMS)-based piezoresistive sensors that confirmed excessive sensitivity and dependable efficiency. Importantly, they built-in these sensors into an insole to create a smart-insole platform.

Utilizing this platform, the staff might monitor the strain distribution on the backside of the foot in actual time, detecting completely different human actions and postures.

“The developed smart-insole system demonstrates the potential of our CNT nanocomposites for 3D printing the subsequent era of extremely stretchable and conductive supplies,” stated Prof. Pyo. “We imagine these supplies will probably be indispensable for wearable well being screens, versatile electronics and sensible textiles.”