Researchers fabricate vascular composite materials

A method for fabricating vascular composite materials with the potential for self-healing and self-cooling has been developed by researchers at the University of Illinois.

The team, part of the Autonomous Materials Systems Laboratory in the Beckman Institute for Advanced Science and Technology, has demonstrated a manufacturing technique that improves on the scalability and commercial viability of previous techniques.

‘We can make a material now that’s truly multifunctional by simply circulating fluids that do different things within the same material system,’ said Scott White, the Willet professor of aerospace engineering who led the group. ‘We have a vascularised structural material that can do almost anything.’

The key to the method, published in the journal Advanced Materials, is the use of sacrificial fibres. The team treated commercially available fibres so that they would degrade at high temperatures. The sacrificial fibres are no different from normal fibres during weaving and composite fabrication, but when the temperature is raised further, the treated fibres vaporise — leaving tiny channels in their place — without affecting the structural composite material itself.

The concept of making fibre-reinforced composites with tiny channels for liquid or gas transport is, in part, inspired by trees on the university campus. The channels could wind through the material in one long line or branch out to form a network of capillaries, much like the vascular network in a tree.

‘Trees are incredible structural materials, but they’re dynamic too,’ said co-author Jeffrey Moore, Murchison-Mallory professor of chemistry and a professor of materials science and engineering. ‘They can pump fluids, transfer mass and energy from the roots to the leaves. This is the first step to making synthetic materials that have that kind of functionality.’

Next, the researchers hope to develop interconnected networks with membranes between neighbouring channels to control transport between channels. Such networks would enable many chemical and energy applications, such as self-healing polymers or fuel cells.

‘This is not just another microfluidic device,’ said co-author Nancy Sottos, Willett professor of materials science and engineering and a professor of aerospace engineering. ‘It’s not just a widget on a chip. It’s a structural material that’s capable of many functions that mimic biological systems. That’s a big jump.’