Laser-patterned polymers enable novel surfaces for electronics

A new way to imprint complex surfaces on low-cost, sustainable polymers could be used in a wide range of industries, including for water-repellent coatings, optical devices and data storage discs.

The complex nano- and micro-scale patterns on sulfur-derived polymers, unveiled in the American Chemical Society ACS Applied Materials and Interfaces journal, build on a wide range of green chemistry solutions led by Flinders University.

“This discovery provides a way to create these technically challenging and time-consuming patterns which can be useful to repel water, prevent biofilm formation and manipulate light in optics applications,” said senior author and ARC Future Fellow Professor Justin Chalker.

“Our team invented a one-step method to make complex patterns on low-cost polymer surfaces using laser light energy without the need for expensive materials. Installing different patterns on the polymer surface can have multiple applications — for example, using water-repellent materials in self-cleaning, anti-fouling and anti-icing surfaces,” Chalker said.

Lead author Dr Abigail Mann, from the Chalker Lab at Flinders University, said using low-power lasers to create these innovative surfaces is an exciting development. “It opens up the possibility of using these intricate polymer surfaces in a wide range of high-value applications,” Mann said.

Senior co-author Dr Christopher Gibson said the modification of polysulfide surfaces with low-power lasers could also support advances in electronics, information storage, biomedical devices, microfluidics and other applications — plus patterns to interact with light and reflect a range of iridescent colours for optics and anti-counterfeiting devices.

The latest trials of microscale patterns on the otherwise black surface of a low-cost sulfur-derived polymer have enabled the creation of structural colour, similar to the iridescent colours observed in butterfly wings and peacock feathers. In anti-counterfeiting devices, this complex pattern could serve as a hidden bar code that can be read with collimated light projected at certain angles.

In the new study, Professor of Physical Chemistry Chiara Neto and other University of Sydney researchers provided expertise in adding nano-texturing, in an aim to create ‘superhydrophobic’ water-repellent surfaces which often require perfluorinated materials linked to the production of harmful PFAS in their manufacture and use.

Image caption: The polymer, made from abundant and inexpensive sulfur from petroleum refining and dicyclopentadiene, is ultra-sensitive to low-power lasers of approximately 1 mW — weaker than a typical laser pointer. Image credit: Flinders University.

Very short exposure times to this low-energy laser light caused swelling in the polymer — something not usually observed with other common polymers or plastics.

Researchers then found the swelling could be controlled, with the size and shape of the modification directly related to the laser exposure time — and the modification was highly stable, persisting for months to years.

This discovery prompted the team to develop a programmable laser system to trace complex patterns on the polymer, installing dots, lines, grids and even exotic patterns that mimic the structure of shark skin.

Top image credit: iStock.com/IURII KRASILNIKOV