How to Make Waterproof Graphene Circuits
Michael Alba posted on January 29, 2018 |
IPG on polyimide can withstand mechanical bending and twisting. (Image courtesy of Nanoscale.)
IPG on polyimide can withstand mechanical bending and twisting. (Image courtesy of Nanoscale.)

New research into inkjet-printed graphene (IPG) has wielded a potential method for printing flexible and waterproof electronic circuits. The new method could prove useful in emerging technologies including flexible electronics, self-cleaning chemical and biological sensors and drag-reducing and de-icing surfaces.

Printed graphene usually requires a post-print annealing process in order to make the graphene conductive, and thus electrically useful. There are a few different annealing processes, including thermal, photonic and laser annealing. The new research revolves around a novel post-print technique that can be used to convert an IPG surface, which is initially hydrophilic and electrically resistive, into a surface that’s hydrophobic and electrically conductive.

Using the energy of a direct-pulsed laser writing (DPLW) technique, the researchers found that they could tune the hydro and electrical properties of the IPG surface. The energy density of the laser corresponds to the degree of hydrophobicity and conductivity in the IPG.

“We’re micro-patterning the surface of the IPG,” explained researcher Jonathan Claussen. “The laser aligns the graphene flakes vertically—like little pyramids stacking up. And that’s what induces the hydrophobicity.”

Top and cross-sectional views(left and right half, respectively) of DPLW-processed graphene compared to thermally annealed graphene (top and bottom half, respectively). (Image courtesy of Nanoscale.)
Top and cross-sectional views(left and right half, respectively) of DPLW-processed graphene compared to thermally annealed graphene (top and bottom half, respectively). (Image courtesy of Nanoscale.)

The method may prove its use in the development of textile-embedded electronics, leading to washable smart fabrics. But flexible, washable electric circuits would be valuable in many different applications.

“One of the things we’d be interested in developing is anti-biofouling materials,” said researcher Loreen Stromberg. “This could eliminate the buildup of biological materials on the surface that would inhibit the optimal performance of devices such as chemical or biological sensors.”

To learn more about the new DPLW process, you can read the researchers’ paper here.


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