Transport at Nanoscale Interfaces

Hybrid Nanoscale Interfaces

Hierarchical composites

Composite materials based on carbon fiber (CF) are prone to failure at the fiber-matrix interface upon compression or stress transverse to the fiber axis. The direct growth of carbon nanotubes on CF constitutes a novel approach to enhance the mechanical properties of the interface.


We present an analysis methodology on ptychographic X-ray computed tomography (PXCT) images in order to assess the iron nanoparticle abundance within CFs. PXCT provides 50 nm - resolved 3D electron density maps of the CFs. We evidence the protective effect of an ultrathin alumina film against iron infiltration into CF during the CNT growth. This method potentially allows to evaluate the efficiency of other diffusion-minimizing approaches. The conclusions of the PXCT examination are validated by energy-dispersive X-ray spectroscopy and scanning transmission electron microscopy carried out on thin sample slices cut with a focused ion beam. The results provide a new insight into the mechanical performance of CFs and therefore constitute valuable knowledge for the development of hierarchical composites.


Collaboration with

Prof. Clemens Dransfeld, FHNW Windisch, Switzerland

Prof Jens Gobrecht, PSI, Switzerland



Protective effect of ultrathin alumina film against diffusion of iron into carbon fiber during growth of carbon nanotubes for hierarchical composites investigated by ptychographic X-ray computed tomography
W. Szmyt, S. Vogel, A. Diaz, M. Holler, J. Gobrecht, M. Calame, and C. Dransfeld.
Carbon, 115, 347-362, 2017

Carbon fibre with and without a protective ultrathin alumina film grafted with carbon nanotubes for hierarchical composites observed by ptychographic X-ray computed tomography.
W. Szmyt, S. Vogel, M. Holler, A. Diaz, J. Gobrecht, M. Calame, and C. Dransfeld.
ECCM17 – 17th European Conference on Composite Materials, Munich, Germany, June 26-30, 2016.

Improved fiber strength of carbon fibers after CNT growth by application of thin Alumina interlayer.
S. Vogel, C. Dransfeld, M. Calame, and J. Gobrecht. 
Proceedings of Composites Week @Leuven and TEXCOMP-11 Conference, Leuven, 16-20 September 2013.