These materials are made up of at least two different phases (matrix and reinforcement) that interact synergistically to bring up new properties. Our aim is to produce composites of tailored properties and functionality: from nanotube loaded polymers for static dissipation to multifunctional composite fibres for smart textiles.
Composite materials are made up of at least two distinguishable phases – usually called matrix and reinforcement – each with different physical and/or chemical properties. A matrix is a continuous phase that holds together one or several reinforcements; reinforcements are discrete particles or fibres that enhance the material's properties (e.g. mechanical strength, electrical and thermal conductivities, abrasion resistance). Synergistic interactions between matrix and reinforcement(s) give composites properties not available from their separate constituents. An example of a natural composite is wood, in which cellulose fibres reinforce a lignin matrix; synthetic composites include concrete, plywood, and the advanced fibre-reinforced polymers used in aerospace and sports applications.
The Macromolecular Materials Laboratory focuses mainly on composites of which one of their phases consists of carbon nanotubes (CNTs): from CNT-reinforced polymers, in which the nanotubes are dispersed in the matrix to enhance the material's strength and electrical conductivity, to composite fibres and films, in which a macroscopic CNT assembly acts as a porous matrix capable of holding large amounts of powders or continuous coatings that lend functionality to the material (e.g. superconductivity, actuation, catalysis, and sensing). We rely on a series of computational and characterisation techniques – including multiscale modeling, Raman spectroscopy, X-ray scattering (SAXS, WAXS), electron microscopy (SEM, HRTEM), mechanical testing (Favimat, DMA), and thermal analysis (TGA, DSC) – to investigate matrix-reinforcement interactions and structure-property relations in our composites. Our ultimate goal is to produce composites of tailored properties and functionality.
People specializing in this area
It has been known for some time that carbon nanotubes have improved the properties of polymer composites. However the quality of the composite depends on the degree of alignment of the nanotubes. The direct spinning method allows us to produce highly aligned nanotubes in fibre form and I am interested in using them as a matrix to provide a framework for superior composite fibres.
The direct spinning process co-synthesises polymeric material which covers the CNT bundles, which we refer to casually as "goo". I am interested the effect of this synthesis by-product and am of the opinion that one way of tailoring the properties of as-spun CNT fibres is to add our own "goo", e.g. with a polymeric material of our own choice.
I investigate the use of Cambridge-made CNT yarns and films as hosts for different functional materials: superconductors, catalysts, polymers, sensing and responsive materials. In the past, I have worked in the incorporation Cu and conductive polymers into the fibres aiming for a composite material with improved conductivity and current carrying capacity.