Regensburg 2010 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 13: Nanoparticles and Viruses

BP 13.1: Hauptvortrag

Dienstag, 23. März 2010, 14:00–14:30, H45

Carbon nanotubes fluids: simple or complex? — •Matteo Pasquali — Department of Chemical & Biomolecular Engineernig, Department of Chemistry, Smalley Institute for Nanoscale Science and Technology, Rice University, Houston Texas, USA

At the single-molecule level, Single-Walled Carbon Nanotubes (SWNTs) have remarkable electrical and mechanical properties, more so than previously known polymer molecules or colloidal particles. Realizing these properties in applications requires understanding and controlling the behavior of SWNTs in dilute as well as concentrated fluid phases. Yet, SWNT liquids are almost considered an oxymoron because dispersing or dissolving SWNTs into fluid phases is exceedingly difficult.

In this talk, I will discuss how SWNTs can and should be viewed as hybrids between polymer molecules and colloidal particles. Even at low concentrations (few parts per million), SWNTs form complex fluid phases with intriguing properties. When stabilized properly, dilute SWNTs behave as Brownian rods. Their interaction can be mediated by polymers and surfactants to produce complex individual architectures, or to devise ways of making transparent conductive coatings. In superacids, SWNTs dissolve spontaneously. At high concentration, they form liquid crystals that can be spun into well-aligned, macroscopic fibers. Intriguingly, the self-assembly of SWNTs into liquid crystalline phases can be understood by hybridizing Onsager's theory for colloidal rods with Flory's theory for rod-like polymers.