Graphene-Based Conductive Ink Delivers a Low-Cost Ballpoint Pen for Drawing Flexible Circuits
Where existing conductive inks are expensive, unstable, or clog a ballpoint pen, this new ink promises dramatic improvements.
A team of scientists at Wuhan University have released a paper detailing a new approach to "drawing" flexible electronics on almost any service, formulating a graphene-based conductive ink which can be fed into a simple ballpoint pen.
Flexible circuits offer a range of benefits above and beyond traditional electronic circuits, not least of which is their ability to follow the contours of almost any surface. While the concept of drawing a flexible circuit using conductive ink isn't new — there are a range of hobbyist-friendly conductive ink suppliers already capitalizing on the market — existing inks are often expensive and much thicker than their non-conductive equivalent, making them better suited to application with a brush than a pen.
In a new research paper, a team claims to have overcome this problem with the development of a conductive ink which doesn't clog a ballpoint pen — and which provides high shelf stability when not in use. The water-based ink includes particles created from graphene nanosheets, carbon nanotubes, and carbon black, bound with rosin resin and stabilized with xanthan gum.
During testing of the ink and pen system, the researchers drew circuits across a variety of surfaces - including, in perhaps the most challenging approach, the rough surface of a loofah. Where possible, the circuits were exposed to multiple folding cycles — demonstrating that even when dry the conductive ink wouldn't shrink or crack and break the circuit.
The team's work has been published in the journal ACS Applied Electronic Materials under closed-access terms.
Article headline image adapted from ACS Applied Electronic Materials 2020, DOI: 10.1021/acsaelm.0c00866
