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7. Composites of carbon nanotubes

Author

Tchoul, Maxim N.

Abstract

Scope and Method of Study: The purpose of this research was to study various methods of incorporation of single-walled carbon nanotubes (SWNT) with polymers for producing electrically conductive polystyrene composites. SWNT of three different types were dispersed in solvents by noncovalent "wrapping" with a semiconjugated copolymer, nitric acid oxidation, and covalent grafting with both polystyrene and poly(vinylbenzyl trimethylammonium chloride). Composites were prepare via solution mixing. Effect of the type of SWNT material and the preparation method on electrical conductivity of the resulting composites was investigated.

Published
2008

8. Improving photocurrent generation: supramolecularly and covalently functionalized single-wall carbon nanotubes-polymer/porphyrin donor-acceptor nanohybrids.

Author

Rahman GMA, Troeger A, Sgobba V, Guldi DM, Jux N, Balbino D, Tchoul MN, Ford WT, Mateo-Alonso A, and Prato M

Subjects
Microscopy, Atomic Force, Microscopy, Electron, Transmission, Molecular Structure, Nanostructures ultrastructure, Nanotubes, Carbon ultrastructure, Photochemistry, Polymers, Spectrophotometry, Nanostructures chemistry, Nanotubes, Carbon chemistry, Porphyrins chemistry
Abstract

Novel nanohybrids based on covalently and noncovalently functionalized single-wall carbon nanotubes (SWNTs) have been prepared and assembled for the construction of photoactive electrodes. Polymer-grafted SWNTs were synthesized by free-radical polymerization of (vinylbenzyl)trimethylammonium chloride. Poly[(vinylbenzyl)trimethylammonium chloride] (PVBTAn+) was also noncovalently wrapped around SWNTs to form stable, positively charged SWNT/PVBTAn+ suspensions in water. Versatile donor-acceptor nanohybrids were prepared by using the electrostatic/van der Waals interactions between covalent SWNT-PVBTAn+ and/or noncovalent SWNT/PVBTAn+ and porphyrins (H2P8- and/or ZnP8-). Several spectroscopic, microscopic, transient, and photoelectrochemical measurements were taken to characterize the resulting supramolecular complexes. Photoexcitation of the nanohybrids afforded long-lived radical ion pairs with lifetimes as long as 2.2 micros. In the final part, photoactive electrodes were constructed by using a layer-by-layer technique on an indium tin oxide covered glass support. Photocurrent measurements gave remarkable internal photon-to-current efficiencies of 3.81 and 9.90 % for the covalent ZnP8-/SWNT-PVBTAn+ and noncovalent ZnP8-/SWNT/PVBTAn+ complex, respectively, when a potential of 0.5 V was applied.

Published
2008
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