Solubilization of Carbon Nanohorns by Block Polyelectrolyte Wrapping and Templated Formation of Gold Nanoparticles

• Published in: Journal of physical chemistry. C 2009-04, Vol.113 (14), p.5444-5449
• Main Authors: Mountrichas, Grigoris, Ichihashi, Toshinari, Pispas, Stergios, Yudasaka, Masako, Iijima, Sumio, Tagmatarchis, Nikos
• Format: Article
• Language: English
• Subjects: C: Nanops and Nanostructures
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp810640h

In this paper, we present a facile method for the noncovalent polymer functionalization of carbon nanohorns (CNHs) using a block polyelectrolyte, leading to water soluble nanohybrid colloids stable for several months. The protocol for the noncovalent functionalization makes use of the amphiphilic poly[sodium (2-sulfamate-3-carboxylate) isoprene-b-styrene] block polyelectrolyte (CSI). The hydrophobic polystyrene block is anchored on the nanohorn surface through hydrophobic interactions, while the polyelectrolyte block stabilizes the formed hybrid nanoassembly through electrosteric interactions. The soluble CNHs/CSI nanoassembly is used as template for the in situ synthesis of gold nanoparticles (Aunano) by reduction of auric acid. The gold nanoparticles are preferentially localized at the periphery of CNHs, because of electrostatic interactions with the charged polymer chains. A variety of complementary techniques, including ATR-IR, UV−vis and EDX spectroscopies, thermogravimetry, dynamic light scattering, and transmission electron microscopy are applied for the characterization and study, in terms of structure and composition, of the CNHs/CSI and CNHs/CSI/Aunano ensembles.