Science loves control. Scientists themselves may be a mixed bunch like anybody else, but when it comes to science, even the branches specializing in disorder, instability and chaos somehow bring the behaviour of these systems in line with expected outcomes. In some ways the ability to harness the erratic and bring governing theories to bear on even the most random variables is part of the thrill, which perhaps explains why whatever your specialism, in materials science it seems all roads lead to multifunctional materials.
“The nice thing about a function compared to a property is that a property is just given by nature – we measure it and it’s a given. A function is the result of a combination of a process with a material,” Andreas Lendlein, told listeners to the webinar at the Multifunctional Materials 2019 board meeting. Lendlein, is Head of Research at Helmholtz Zentrum’s Teltow-Seehof Site, Director of the Institute of Biomaterial Science and joint Editor-in-Chief of Multifunctional Materials alongside University of Bristol’s Richard Trask. Members of the journal’s editorial board attended the webinar in person to share ideas to remote listeners around the world. Lendlein went on to describe how a function has an input – which can be environmental factors, stimuli or some kind of signal – and an output, otherwise loosely described as the effect. There in a nutshell is how studies of functional materials can introduce an element of control, or at the very least predictability, and how multifunctional materials can allow that control to diversify.
Challenges
The aims set forward in the webinar were far from modest: zero emission transport; theranostic drug delivery with not just controlled release but controlled degradation in the delivery vesicle; superseding silicon with flexible materials that are sustainable as well as smart; and manufacturing lines for growing not just structures but active structures with robotic behaviour. One of the keys to success in multifunctional materials research, it seems, is people.
Multifunctional carbon fibres enable massless energy storage
Leif Asp, a professor at Chalmers University of Technology in Sweden described some of the work he is engaged in to develop carbon fibre composites for vehicles where the frame itself takes on energy storage functions. These structural batteries could mitigate against the usually high load battery masses bring to devices, but as Leif points out their development relies on a large team of researchers from a wide range of disciplines.
“For populating the models we need to work with a huge number of properties like the diffusion coefficient – which are not known for carbon fibres, not in a good way,” he told attendees and remote listeners. “The grand challenge may be zero emission transportation, but the smaller challenge is the size of the team needed.”
In medical applications, the necessary regulatory hurdles add pressure to keep innovations simple as well as smart, explained Benjamin Nottelet from the University of Montpellier in France. Following on a summary of research in 3- and 4D printing by board member Jerry Qi from Georgia Institute of Technology in the US, Nottelet suggested one challenge might be to combine technologies like macromolecular engineering with 3D printing.
With the imminent demise of the planet at stake, the composition and source of new materials matter more than ever. As Philippe Poulin from the University of Bordeaux suggested, this includes finding alternatives to rare earth metals and sourcing polymers from biological matter instead of petroleum. “Certainly it’s a challenge for all of us to think about how these materials will leave a lasting footprint on our planet,” added Trask, who moderated the discussion.
Opportunities
Despite the challenges, opportunities in progressing multifunctional materials seem ripe. Working with biological systems presents opportunities in robotics where, as Stoyan Smoukov at Queen Mary University in the UK points out, future decreases in size and increases in production will require fundamental changes in how robots operate. “We have to think of making the materials the robots – joints and motors and all kinds of structures in current robots – we have to include all the functionality in the material itself,” he said. “We can either make completely artificial robots or we can use cyborg materials – which can be the intermediate stages of the next step of evolution.”
Grand challenges of multifunctional materials
More generally, climate change aside, Martin Dunn from the University of Colorado suggested that we are currently witnessing a perfect storm of new materials merging with new manufacturing methods overlaying an “exploding culture of innovation entrepreneurship”. Additive manufacturing developments have contributed here with, as Qi pointed out, affordable 3D printers shortening the innovation cycle and inspiring “grass roots” innovation.
In response to the question “How will design of multifunctional materials occur in the future?” Dunn highlighted creative efforts to exploit nonlinear behaviour to trigger instabilities like buckling, as well as functions designed for sustainability, which affects the business case. He then asked, “What are the skill sets of designers going to be? How will we get them and how will we educate them? I think designing materials in teams is going to be really important but they are going to be augmented by new computational and data-driven tools that allow them to cycle through design options faster.”
You can watch the recorded webinar in full at Grand challenges of multifunctional materials.
