High-power lasers are often used to modify polymer surfaces to make high-tech biomedical products, electronics and data storage components. Now, Flinders University researchers have dis­covered a light-responsive, inexpensive sulfur-derived polymer is receptive to low power, visible light lasers – promising a more affordable and safer production method in nanotech, chemical science and patterning surfaces in biological appli­cations.

“This could be a way to reduce the need for expensive, specialised equipment including high-power lasers with  hazardous radiation risk, while also using more sustainable materials. For instance, the key polymer is made from low-cost elemental sulfur, an industrial byproduct, and either cyclo­pentadiene or dicyclo­pentadiene,” says Justin Chalker from the Flinders University. “Our study used a suite of lasers with discreet wavelengths (532, 638 and 786 nanometers) and powers to demonstrate a variety of surface modi­fications on the special polymers, including controlled swelling or etching via ablation. The facile synthesis and laser modi­fication of these photo-sensitive polymer systems were exploited in appli­cations such as direct-write laser litho­graphy and erasable information storage.”

As soon as the laser light touches the surface, the polymer will swell or etch a pit to fashion lines, holes, spikes and channels instantly. The discovery was made by Flinders University researcher and Christopher Gibson during what was thought to be a routine analysis of a polymer first invented in the Chalker Lab in 2022 by PhD candidate Samuel Tonkin and Justin Chalker. Gibson says: “The novel polymer was immediately modified by a low-power lasers – an unusual response I had never observed before on any other common polymers. We immediately realised that this phenomenon might be useful in a number of appli­cations, so we built a research project around the discovery.” 

PhD candidate Abigail Mann led the next stage of the project. “The outcome of these efforts is a new technology for generating precise patterns on the polymer surface,” she says. “It is exciting to develop and bring new micro­fabrication techniques to sulfur-based materials. We hope to inspire a broad range of real-world applications in our lab and beyond.”

Potential applications include new approaches to storing data on polymers, new patterned surfaces for biomedical appli­cations, and new ways to make micro- and nanoscale devices for electronics, sensors and micro­fluidics. With support from  Lynn Lisboa and Samuel Tonkin, the team conducted detailed analysis of how the laser modifies the polymer and how to control the type and size of modification.

Lynn Lisboa adds: “The impact of this discovery extends far beyond the laboratory, with potential use in biomedical devices, electronics, information storage, microfluidics, and many other functional material appli­cations.” Spectro­scopist Jason Gascooke of the Australian National Fabri­cation Facility (ANFF) also worked on the project. He says the latest discovery would not have been possible without the tools afforded by Federal and State Government funding for the national facilities of Microscopy Australia and the ANFF in SA, as well as Flinders Microscopy and Micro­analysis. (Source: Flinders U.)

Reference: A. K. Mann et al.: Modification of Polysulfide Surfaces with Low-Power Lasers, Ang. Chem. Int. Ed., online 19 March 2024; DOI: 10.1002/anie.202404802

Link: Institute for Nanoscale Science and Technology, College of Science and Engineering, Flinders University, Bedford Park, Australia