3D-printed carbon nanotube sensors present potential for good 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 tough to work with as they have a tendency to agglomerate, making it exhausting to acquire a uniform dispersion. Furthermore, typical strategies restrict management over CNT distribution and form.

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

On this methodology, a lightweight is used to selectively treatment and harden layers of an ink inside a vat, regularly 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 serious 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 Know-how 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 gadget.”

Their research is revealed within the journal Composite Buildings.

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 steadiness of properties.

It might stretch as much as 223% of its unique 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 totally different human actions and postures.

“The developed smart-insole gadget demonstrates the potential of our CNT nanocomposites for 3D printing the subsequent era of extremely stretchable and conductive supplies,” stated Prof. Pyo. “We consider these supplies might be indispensable for wearable well being displays, versatile electronics and good textiles.”