A group of researchers are using laser processing to develop stronger fibres, which could be used to create better bike helmets, longer-lasting batteries and improved medical devices.
Fibres are used in virtually every industry – from aerospace to athletics, energy to health care.
Scientists have long worked to develop stronger, better fibres, however researchers from Rowan University in New Jersey claim that they are now working to create the strongest polymer fibres to ever exist.
‘Our inspiration is to engineer materials that are the highest performance that anyone can create,’ said Dr Vince Beachley who is leading the work.
Beachley and his team aim to create techniques that can be used on a large scale – enabling companies to manufacture these ‘super fibres’ for an array of applications that benefit society. The fibres would be incorporated in various ways, for example as membrane-thin sheets in devices, or fibres embedded in composites to create strong structural materials.
The team recently received a $523,000 grant from the National Science Foundation to research and refine their methods over the next three years. They aim to develop a systematic understanding of how certain fibres are affected and strengthened by various levels of heat, temperature, and force used for stretching. Extensive experiments will be conducted and mathematical models created.
Laser heating
Doctoral student Matthew Flamini came up with a novel way to heat the project’s ultra-thin nanofibres, which are about 1/200th the width of a human hair, using a laser.
The laser beam’s heat makes the nanofibres pliable so they can be stretched, which causes their molecules to align in a chain. The fibres must then be cooled quickly so the molecules lock into place, strengthening the barely visible strands.
Prior research on nanofibres has used heating elements or solvents to soften them. However, the laser's precision enables the researchers to quickly scan the beam over each fibre, sequentially heating and cooling a millimetre or so at a time, reducing the chances of breakage.
The researchers hypothesise that nanofibres can be made stronger than thicker fibres, due to their high ratio of surface area to volume, which enables faster heating and cooling.
Potential for scaling up
The researchers will also use another promising technology for their work: a track system pioneered by Beachley and refined over the past decade. The automated device – which looks a bit like a loom – holds, moves, and stretches each fibre as the laser heats the strands, section by section.
'The track system is what makes this scalable,' explained Beachley. 'We can run thousands of fibres per minute with a single laser source.'
Many types of fibres can be engineered, including nylon, polyester, polyethylene, and carbon. Flamini is especially excited to work on a biodegradable poly(lactic acid) (PLA) fibre approved by the Food and Drug Administration for biomedical uses. By enhancing PLA nanofibres, for example, 'we could make them last longer inside the body' and fine-tune their abilities to absorb and release medications, he suggested.
The researchers believe this work will lay vital foundations for future applications that no one has yet imagined.
‘We think the sky's the limit,’ concluded Beachley.
