We have developed a model for the calculation of van der Waals force for layered systems with axial symmetry. Our result can be applied to compute the cohesion of a carbon nanotube to a substrate, the cohesion between nanotubes, and between shells of multiwall nanotubes. We have obtained unusal power laws for the distance dependence of the many-body van der Waals potential.

We have fabricated ordered arrays of nanoscale torsional actuators consisting of metal mirrors bonded to precisely oriented multiwall carbon nanotubes. The fabrication is facilitated by a new nanotube positioning method which employs localized electron beam activation of polymer residue on a silicon oxide surface.

In this study, we investigated the chemical functionalization of carboxylated multiwalled carbon nanotubes (MWCNT–COOH) by 1-Amino-2-naphthol-4-sulfonic acid (ANSA). The functionalized MWCNTs exhibited good aqueous solubility due to the presence of the –OH and – SO3H groups of ANSA. The antimicrobial activity of the MWCNT–COOH as well as its functionalized multiwall nanotube MWCNT-CO-2-(1-amino...

The field emission of individual multiwall carbon nanotubes grown by chemical vapor deposition was measured in a scanning electron microscope. By using a sharp anode, we were able to select one nanotube for measurements in carefully controlled conditions. Single nanotubes follow the Fowler-Nordheim law, and the dependence of the field enhancement with interelectrode distance and nanotube radius...

To understand diffusion processes occurring inside Fe catalysts during multiwall carbon nanotube (MWCNT) growth, catalysts were studied using atomic-resolution scanning transmission electron microscopy combined with electron energy-loss spectroscopy. Nanotube walls emanate from structurally modified and chemically complex catalysts that consist of cementite and a 5 nm amorphous FeOx cap separat...

Conventional metallic strain sensors are flexible, but they can sustain maximum strains of only ~5%, so there is a need for sensors that can bear high strains for multifunctional applications. In this study, we report stretchable and flexible high-strain sensors that consist of entangled and randomly distributed multiwall carbon nanotubes or graphite flakes on a natural rubber substrate. Carbon...

A significant resonant tunneling effect has been observed under the 2.4 V junction threshold in a large area, carbon nanotube-silicon (CNT-Si) heterojunction obtained by growing a continuous layer of multiwall carbon nanotubes on an n-doped silicon substrate. The multiwall carbon nanostructures were grown by a chemical vapor deposition (CVD) technique on a 60 nm thick, silicon nitride layer, de...

nanotechnology is the study of manipulating matter on an atomic and molecular scale. generally, nanotechnology deals with developing materials, devices, or other structures possessing at least one dimension size from 1 to 100 nanometers .  carbon nanotubes have great potentials for novel applications in industry, drug delivery system and many other uses. in this work after purification, multiwa...

The excellent mechanical properties of carbon nanotubes (CNTS) are driving research into the creation of new strong, tough nanocomposite systems. Here, the first evidence of toughening mechanisms operating in carbon-nanotube-reinforced ceramic composites is presented. A highly ordered array of parallel multiwall CNTs in an alumina matrix was fabricated. Nanoindentation introduced controlled cra...

Aligning multiwall carbon nanotubes (MWNTs) with the direction of load is desirable for maximizing tensile reinforcement in composites. This has been accomplished by spinning composite fibers containing MWNTs[1]. The shear and elongational flow fields inherent to fiber processing cause the MWNTs to align with the fiber axis. Efficient stress transfer from the matrix to the MWNTs is also a cruci...