Imperial College London Background
Carbon Fibre (CF) composites are state-of-the-art structural materials with excellent tensile properties, but there are critical limiting factors associated with the fibre-matrix interface, such as poor compression performance and poor interlaminar toughness.
Chemical Vapour Deposition (CVD) used to synthesise Carbon nanotubes (CNTs) in-situ on primary fibres is simple, economic and has shown promising results. However, on CF the CVD process typically leads to damage of the underlying CF substrate through catalyst pitting, reducing the primary properties of interest. While protective coatings can mitigate this, they create an additional weak interface and limit anticipated benefits.
A modification of the CVD process can produce CNT-g-CF without causing damage or requiring a coating. Applying a potential difference to the catalyst loaded CF tow, such that the growth occurs in an electric field, encourages uniform CNT growth without degrading the primary mechanical properties. The approach can be easily incorporated into continuous industrial production. In addition, the process can be used to graft short (sub 0.3 μm), small diameter CNTs, such that the fibre volume fraction of primary fibres may be retained in the final consolidated composite .
Anthony, D. B., Sui, X., Kellersztein, I., De Luca, H. G., White, E. R., Wagner, H. D., … & Shaffer, M. S. (2018). Continuous carbon nanotube synthesis on charged carbon fibers. Composites Part A: Applied Science and Manufacturing, 112, 525-538.
Anthony, D. B., Qian, H., Clancy, A. J., Greenhalgh, E. S., Bismarck, A., & Shaffer, M. S. (2017). Applying a potential difference to minimise damage to carbon fibres during carbon nanotube grafting by chemical vapour deposition. Nanotechnology, 28(30), 305602.
CNT grafted CFs with superior material properties
CF tow left undamaged without need for barrier coatings or vacuum processes
Uniform aligned and densely packed CNT growth within and along the carbon fibre tow
Uniquely suitable for structural composite applications
This novel production method can be applied to an open-ended chemical vapour deposition reactor in a continuous fashion and can be easily incorporated into continuous industrial production of carbon nanotube grafted carbon fibres (CNT-g-CF) without causing any damage or requiring a coating. The invention is simple and comparable with existing carbon fibre processing, thus requiring minimal retooling, equipment and capital investment.