What if, instead of becoming obsolete once damaged, electronics could heal and repair themselves? That's the promise of a new, flexible, and conductive composite designed for sustainable electronics. Assistant Professor Mohammad Malakooti sat down with AZoMaterials to explain why this innovation is important and how his team brought it to life.
Most electronic materials are built to last: stable, heat-resistant, and hard. At the same time, with advances in miniaturization and technology, computer hardware has become ever more complicated to break down and recycle.
As a result, our landfills are becoming increasingly populated with e-waste. Toxic and long-lasting, this is a significant concern. With their newly published research in Advanced Functional Materials, scientists at the University of Washington are exploring new approaches to tackle this challenge.
Why is it so important that research scientists start considering a circular approach during development?
The growing amount of discarded consumer electronics has created serious environmental concerns. At the same time, we’re facing limited material resources and rising global metal costs.
I think it’s important for researchers like us, who work on emerging technologies, to consider recyclability from the start and ensure our solutions are sustainable throughout their entire life cycle.
Can you explain the key findings? How does the composite work? And how did you land on the combination of materials you did?
Our team has developed a soft, stretchable material that can conduct electricity, heal itself if damaged, and be reused or recycled.
The composite is made from a special polymer called vitrimer, which is flexible and recyclable, and tiny droplets of a liquid metal alloy based on gallium. The liquid metal droplets carry an electrical current when they are connected within the polymer.
I’ve been working with liquid metals for about eight years, studying new ways to use them in flexible and wearable electronics. We chose this polymer after talking with my friend Chris Bowland from my PhD days.
His team at Oak Ridge National Laboratory had used this polymer in other recyclable composites, which inspired our collaboration and led to the development of liquid metal vitrimer composites.
Read the news release here!
What is the current energetic requirement of the chemical decomposition method, and how could that be improved for the material to be even greener in its recyclability?
We tested different ways to make the composite and varied the size and amount of liquid metal droplets to see how they affected the material. We also looked at how the droplets spread and connect, which influences conductivity.
Finally, we ran tests to make sure the material could stretch, heal itself, and be recycled effectively.
Currently, the chemical process we use to separate the liquid metal from the polymer involves heating and using a solvent and an acid.
This allows us to recover over 94 % of the metal, which is great, but we hope to reduce the energy required and use milder chemical conditions.
These improvements would make the material greener and the recycling process even more environmentally friendly.
Where do you hope to see this go? For instance, what industries could this be used in, and what are your next steps going forward?
We hope this material will be used by big tech companies and startups that are working to reduce electronic waste and recover valuable metals.
Its flexibility, self-healing ability, and recyclability make it especially promising for applications like soft robotics, smart patches, and electronic biosensors.
Our next steps are to conduct more fundamental studies to understand these composites better, experimenting with different processing methods and vitrimers, figuring out their limitations, and testing how they could be used in device fabrication.
Could you tell us more about the project and how it was conducted?
This paper actually grew out of an NSF-funded internship I secured for my PhD student, Youngshang Han, the first author.
He traveled to Tennessee to work at ORNL on this project, and I also visited and gave a talk as part of an effort to connect academia and industry. We then continued the work on the project and completed it back at UW in Seattle.
This project really highlights the value of collaboration between students, labs, and institutions. It shows how supporting young researchers through programs like NSF internships can lead to exciting and impactful scientific discoveries.
About Mohammad Malakooti and the Team
Dr. Mohammad H. Malakooti is an Assistant Professor of Mechanical Engineering at the University of Washington, where he leads the iMatter Lab. He recently won his third ASME award for excellence in his contributions to the field of mechanical engineering research. His team creates materials that match the extraordinary adaptability, rich multifunctionality, and embodied intelligence of natural systems. He received his Ph.D. from the University of Florida, completed a Postdoctoral Fellowship at the University of Michigan, and was a Research Scientist at Carnegie Mellon University.
The co-authors of the study include Youngshang Han, a UW doctoral student of mechanical engineering; Shreya Paul, a UW undergraduate student of mechanical engineering; and Sargun Singh Rohewal, Sumit Gupta ,and Christopher C. Bowland at the Oak Ridge National Laboratory.
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