Chemical Vapour Deposition (CVD) of Vertically Aligned Carbon Nanotubes (VANTAs)
Kiowski O., Lebedkin S., Hennrich F., Malik S., Rösner H., Arnold K., Sürgers C., Kappes M. M.; PRB 75, 075421/1-7, (2007)
Graphene Synthesis by Intercalation of HOPG
(a) and (b) HOPG before expansion, (c) HOPG after intercalation and expansion.
Atomic resolution, aberration-corrected TEM detail of graphene flakes
(a) HRTEM micrograph of few-layer high purity graphene prepared by a chemical intercalation method. (b) HRTEM detail revealing the presence of clean, single, and bi-layer graphene areas.
S. Malik, A. Vijayaraghavan, R. Erni, K. Ariga, I. Khalakhan, J. P. Hill; Nanoscale 2, 2139 (2010)
Branched-Multi-Walled Carbon Nanotubes (b-MWCNTs) - an exotic type of carbon nanotube whose technological potential has not yet been fully explored
Carbon nanotubes (CNTs) have atomically smooth surfaces and tend not to form covalent bonds with composite matrix materials. Thus, it is the magnitude of the CNT/fiber interfacial strength which limits the amount of nanomechanical interlocking when using conventional CNTs to improve the structural behavior of composite materials through reinforcement.
a) HRTEM overview of branched-MWCNTs and b) HRTEM detail of Y-pattern b-MWCNTs, c) and d) HRTEM detail of T-pattern b-MWCNTs.
Two main issues are widely recognized as being critical for the development of mechanically efficient nanocomposites: (1) adequate dispersion of the nano-reinforcement filler within the matrix, and (2) strong interfacial bonding between the reinforcement element and matrix. This arises from poor dispersion of the CNTs which in turn leads to aggregation in certain areas of the matrix. However, a network of branched CNTs would significantly reduce this network resistance (Figure 1). This would provide major benefits to the existing commercial application of CNT reinforced composites in Electrostatic Discharge Materials (ESD) as well as potential usage in Supercapacitors, Solar Cells and Li-Ion batteries.
S. Malik, Y. Nemoto, H. Guo, K. Ariga and J. P. Hill; Beilstein J. Nanotechnol. 7, 1260-1266 (2016)