In brief

Using the covalent adaptable network concept, researchers created a library of covalently crosslinked nanofibres that, unlike their predecessors, are both resilient and reusable to enable applications ranging from energy storage to drug delivery.

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Weaving the threads of sustainable nanofibres

25 Jul 2023

Researchers develop a new class of recyclable polymer-based nanofibres with exceptional strength and durability.

Nanofibres are a hundred times thinner than human hair and over ten times stronger than steel. These tiny yet mighty synthetic polymers are transforming many medical and industrial applications—from safely delivering patients their medications to boosting the performance of solar panels.

Traditional polymers such as thermosets or thermoplastics are typically used as the building blocks of these minuscule fibres. However, materials scientists have faced a tug-of-war between durability and recyclability which has hampered efforts to expand the application landscape of nanofibres.

This limitation inspired Zibiao Li, Director of the Sustainable and Green Materials division at A*STAR’s Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), to develop a new class of ‘green’ polymers for next-generation nanofibres.

“We believe the solution lies in covalent adaptable networks, or CANs—a unique type of polymer that combines the best of both worlds of thermosets and thermoplastics,” said Li. “CANs boast unique and versatile chemical structures that lend the polymer stability and robustness, while also granting it the flexibility necessary for recycling."

Together with colleagues from A*STAR's Institute of Materials Research and Engineering (IMRE) and collaborating with researchers from King Abdullah University of Science and Technology, Saudi Arabia, and Chinese Academy of Sciences, China, Li leveraged CANs to engineer a suite of dynamic covalently crosslinked nanofibres (DCCNFs).

Next, the team subjected the nanofibres to a range of stress and thermal tests. They discovered that compared to traditional nanofibres, DCCNFs can bear more heat, endure more stress and maintain their shape, even when exposed to harsh chemicals.

Schematic representation of the one-pot closed-loop recycling process for a 60 °C DCCNF, showing how the covalent bonds crosslinking nanofibres break and reform at each stage.

©️ A*STAR Research

“The DCCNFs can also respond to different stimuli, making them repairable and recyclable,” Li explained. "Remarkably, even after the recycling process, the nanofibres retain their original shape and demonstrate no significant degradation in their performance."

Given these unique attributes, DCCNFs may enable applications that span membrane technologies, electronics, smart textiles and energy-harvesting devices, among others.

“We are also exploring the potential of DCCNF in various fields, such as separation membranes and flexible electronics,” added Li. “Our goal is to contribute to the development of innovative and sustainable technologies that bring about positive societal change.”

The A*STAR-affiliated researchers contributing to this research are from the Institute of Sustainability for Chemicals, Energy and Environment (ISCE2) and the Institute of Materials Research and Engineering (IMRE).

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Wang, S., Wang, N., Kai, D., Li, B., Wu, J., et al. In-situ forming dynamic covalently crosslinked nanofibers with one-pot closed-loop recyclability. Nature Communications 14, 1182 (2023).│article

About the Researchers

Zibiao Li is the Director of the Sustainable and Green Materials division at A*STAR’s Institute of Sustainability for Chemicals, Energy and Environment (ISCE2), where he leads a research group working on sustainable polymers towards a circular materials economy. Li holds a joint appointment at the Institute of Materials Research and Engineering (IMRE) and is an adjunct Associate Professor at the National University of Singapore (NUS). His research interests focus on materials sustainability and MedTech polymers for healthcare applications.
Bofan Li obtained her BEng (2016) and PhD (2021) in chemical engineering from the National University of Singapore. She is currently working as a Research Scientist at A*STAR's Institute of Sustainability for Chemicals, Energy and Environment (ISCE2). Her research interests are focused on the design and development of smart and sustainable membranes for water purification and organic solvent separations.

This article was made for A*STAR Research by Wildtype Media Group