The catalytic chemical vapor deposition (CCVD) is currently the most flexible and economically attractive method for the growth of carbon nanotubes. Although its principle is simple, the precisely controlled growth of carbon nanotubes remains very complex because many different parameters influence the growth process. In this article, we review our recent results obtained on the synthesis of carbon nanotubes via CCVD. We discuss the role of the catalyst and the catalyst support. Our recent results obtained from the water assisted growth and the equimolar C2H2-CO2 reaction are also discussed. Both procedures lead to significantly enhanced carbon nanotube growth. In particular, the latter allows growing carbon nanotubes on diverse substrate materials at low temperatures.

In many applications like photovoltaics, fuel cells, batteries, or interconnects in integrated circuits carbon nanotubes (CNTs) have the role of charge transport electrodes. The building of such devices requires an in situ growth of CNTs at temperatures where the structure or chemical composition of the functional materials is unaltered. We report that in a chemical vapor deposition process involving an oxidative dehydrogenation reaction of C2H2 with CO2 growth temperatures below 400 degrees C are achieved. Furthermore, the growth can be performed on versatile materials ranging from metals through oxides to organic materials.

Biomaterials are constructed from limited sets of building blocks but exhibit extraordinary and versatile properties, because hierarchical structure formation lets them employ identical supramolecular motifs for different purposes. Here we exert a similar degree of structural control in synthetic supramolecular elastomers and thus tailor them for a broad range of thermomechanical properties. We show that oligopeptide-terminated polymers selectively self-assemble into small aggregates or nanofibrils, depending on the length of the oligopeptides. This process is self-sorting if differently long oligopeptides are combined so that different nanostructures coexist in bulk mixtures. Blends of polymers with oligopeptides matching in length furnish reinforced elastomers that exhibit shear moduli one order of magnitude higher than the parent polymers. By contrast, novel interpenetrating supramolecular networks that display excellent vibration damping properties are obtained from blends comprising non-matching oligopeptides or unmodified polymers. Hence, blends of oligopeptide-modified polymers constitute a toolbox for tailored elastomers with versatile properties.

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We have characterized the electrical conductivity of the composite which consists of multi-walled carbon nanotubes dispersed in SU8 epoxy resin. Depending on the processing conditions of the epoxy (ranging from non-polymerized to cross-linked) we obtained tunneling and percolating-like regimes of the electrical conductivity of the composites. We interpret the observed qualitative change of the conductivity behavior in terms of reduced separation between the nanotubes induced by polymerization of the epoxy matrix.Carbon nanotubes, 20 years after their discovery are in the stage where the focus is more and more on their applications. The physical properties which are beneficial for applications are good electrical conductivity (σ), exceptionally high thermal conductivity, and their high mechanical strength. These properties are preferentially used in composites, where carbon nanotube fillers can provide the missing property of the matrix, for example the electrical conductivity. The metallic carbon nanotubes (CNTs) added in concentrations beyond the percolation threshold to the insulating matrix can give an antistatic composite, 1 transparent conducting electrode, 2 or other large area conducting materials. 3 In composite materials, one main issue is the possibility of combining the properties of the filler with those of the matrix. In this respect, SU8 matrix, which is a well-established engineering material for micro-and nano-fabrication, offers wide range opportunities. SU8 is an epoxy-based, negative-tone, UV-sensitive photoresist which besides SU8 resin, contains an organic solvent and a photoinitiator (PI) to provide crosslinking of the oligomers (see a schematic representation of the SU8 epoxy in Fig. 1). 4 One of the great advantages of SU8 is that it can allows fabrication of high aspect ratio three-dimensional structures in a broad range of thicknesses and hence it is often used in nano-and macrometer sized devices. 5 The disadvantages of SU8 are that it is an electrical insulator, it is brittle and it has a low thermal conductivity. It would be desirable not to have all these drawbacks, so numerous fillers materials were used to prepare SU8-based composites. [6][7][8] Here we report the electrical conduction of multi-walled carbon nanotubes-SU8 composite materials (hereafter CNTs-SU8) for a broad concentration range of well-dispersed CNTs. The CNTs-SU8 inks were prepared with and without PI, giving composites with and without cross-linked matrix, respectively. From the theoretical point of view, these two cases are equivalent to study the conduction mechanism of an assembly of CNTs in a solid and in a "liquid" matrix. Interestingly, beside the effects on the conductivity level, the functional dependence of σ on the CNTs' content noticeably differs for these two cases. a) Current address: Powder Technology Laboratory, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland Multiwalled CNTs were synthesized by the chemical vapor decomposition method (CVD) at 640 • C using Fe-Co catalytic pa...