In Situ Measurements of Nanotube Dimensions in Suspensions by Depolarized Dynamic Light Scattering

We show that the dimensions of carbon nanotubes (CNTs) in suspension can be characterized by depolarized dynamic light scattering. Taking advantages of this in situ technique, we investigate in detail the influence of sonication procedures on the length and diameter of CNTs in surfactant solutions. Sonication power is shown to be particularly efficient at unbundling nanotubes, whereas a long sonication time at low power can be sufficient to cut the bundles with limited unbundling. We finally demonstrate the influence of CNT dimensions on the electrical properties of CNT fibers. Slightly varying the sonication conditions, and thereby the suspended nanotube dimensions, can affect the fibers conductivity by almost 2 orders of magnitude

Liquid Crystal Behavior of Single-Walled Carbon Nanotubes Dispersed in Biological Hyaluronic Acid Solutions

We report the spontaneous liquid crystal phase separation of nanotubes (single-walled carbon nanotubes, SWNTs) stabilized in aqueous biological (hyaluronic acid, HA) solutions. Sonication of SWNTs in solutions of HA produced well-dispersed single-phase isotropic dispersions which, over time, phase separated into dispersions containing birefringent nematic domains in equilibrium with an isotropic phase. The time required for phase separation to occur was shown to depend on the concentration of SWNT and HA, with the attractive interactions between the SWNT and HA shifting the onset of the phase separation toward lower concentration. This phase separation is accompanied by an increase in the dispersion viscosity with this increase qualitatively matching the degree of phase separation. The formation of ordered phases in biological media can offer wide opportunities for processing conducting biomaterials with aligned and oriented domains

Self-Assembled Tin-Based Bridged Hybrid Materials

Hybrid materials where layers of tin oxide alternate with layers of hydrophobic organic chains were prepared by the hydrolysis of distannylated compounds containing an organic chain α,ω-disubstituted by tripropynylstannyl groups. In the case of an aliphatic chain, hydrolysis under microemulsion conditions led to the organization of the corresponding hybrid. These hydrolysis conditions also induced a high surface area and a defined mesoporosity in the hybrid. When a mixed aromatic−aliphatic spacer was used, weak hydrophobic interactions between the spacers were sufficient to generate the same type of organization in the corresponding material

Self-Assembled Tin-Based Bridged Hybrid Materials

Hybrid materials where layers of tin oxide alternate with layers of hydrophobic organic chains were prepared by the hydrolysis of distannylated compounds containing an organic chain α,ω-disubstituted by tripropynylstannyl groups. In the case of an aliphatic chain, hydrolysis under microemulsion conditions led to the organization of the corresponding hybrid. These hydrolysis conditions also induced a high surface area and a defined mesoporosity in the hybrid. When a mixed aromatic−aliphatic spacer was used, weak hydrophobic interactions between the spacers were sufficient to generate the same type of organization in the corresponding material