Bioaccumulation and ecotoxicity of carbon nanotubes

Carbon nanotubes (CNT) have numerous industrial applications and may be released to the environment. In the aquatic environment, pristine or functionalized CNT have different dispersion behavior, potentially leading to different risks of exposure along the water column. Data included in this review indicate that CNT do not cross biological barriers readily. When internalized, only a minimal fraction of CNT translocate into organism body compartments. The reported CNT toxicity depends on exposure conditions, model organism, CNT-type, dispersion state and concentration. In the ecotoxicological tests, the aquatic organisms were generally found to be more sensitive than terrestrial organisms. Invertebrates were more sensitive than vertebrates. Single-walled CNT were found to be more toxic than double-/multi-walled CNT. Generally, the effect concentrations documented in literature were above current modeled average environmental concentrations. Measurement data are needed for estimation of environmental no-effect concentrations. Future studies with benchmark materials are needed to generate comparable results. Studies have to include better characterization of the starting materials, of the dispersions and of the biological fate, to obtain better knowledge of the exposure/effect relationships

The state of things: state history and theory reconfigured

This article looks at the relationship between logistical power and the assemblages of sites that constitute modern states. Rather than treating states as centralizing institutions and singular sites of power, we treat them as multi-sited. They gain power by using logistical methods of problem solving, using infrastructures to enforce and depersonalize relations of domination and limit the autonomy of elites. But states necessarily solve diverse problems by different means in multiple locations. So, educating children is not continuous with governing colonies even though both are necessary to nineteenth-century states. For this reason, states use logistical means of coordination to link sites, and they make the power of the state seem unitary even though the exercise of state power is not

Supramolecular Chemistry of Carbon Nanotubes at Interfaces: Toward Applications

The properties at interfaces play important roles in biology and electronics. In the last 20 years, new carbon allotropes, like carbon nanotubes, have emerged as novel suitable substrates for the production of derivatives with wide range of technological applications. Since then, a great attention has been drawn in the study of the biological and technological properties of these novel allotropes at interfaces. Among the plethora of chemical reactions adopted to improve the properties of these nanostructured carbon species, the one employing supramolecular approaches have rapidly increased during the last years. In this chapter we will review the supramolecular approaches aimed at the functionalization of these carbon-based nanostructures focusing on their properties and applicative uses as self-organized materials at interfaces

Supramolecular Chemistry of Carbon Nanotubes

International audienceThis chapter aims to present recent examples of supramolecular functionalization of carbon nanotubes. The non-covalent functionalization appears as a solution for the future applications in nanotechnologies since it allows the functionalization and manipulation of nanotubes without the introduction of sp 3 defects in the π-conjugated system. Thus, the optical and electronic properties of the nanotubes remain preserved. In the first part of this chapter, we present the use of surfactant for the dispersion of nanotubes and its application for sorting. Then we report several examples of functionalization of nanotubes based on π-stacking interactions with pyrene derivatives. Finally, in the last part we review the wrapping of photo/electroactive polymers around the nanotube sidewalls. We put a particular focus on polyflurorene-based polymers and we show their utilization for the separation of nanotubes in diameter and chirality