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

Polymer-based conductive nanocomposites, notably these incorporating carbon nanotubes, are extremely promising for the event of versatile electronics, tender robotics and wearable units. Nevertheless, CNTs are tough to work with as they have an inclination to agglomerate, making it onerous 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, comparable to vat photopolymerization (VPP), which provide wonderful design freedom with excessive printing accuracy.

On this technique, a light-weight 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 reaching excessive stretchability and electrical conductivity is a significant problem.

Now, a analysis workforce 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 complicated 3D buildings,” 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 printed within the journal Composite Buildings.

The workforce 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 circumstances.

Subsequent, the workforce additively manufactured check specimens utilizing the varied 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 provided the perfect steadiness of properties.

It may stretch as much as 223% of its unique size earlier than breaking, whereas nonetheless reaching a exceptional 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 reveal 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 workforce may monitor the strain distribution on the backside of the foot in actual time, detecting totally 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 consider these supplies will probably be indispensable for wearable well being screens, versatile electronics and sensible textiles.”