Surface oxidation of single wall carbon nanohorns for the production of surfactant free water-based colloids

Filippo Agresti; Simona Barison; Alessia Famengo; Cesare Pagura; Laura Fedele; Stefano Rossi; Sergio Bobbo; Marzio Rancan; Monica Fabrizio

doi:10.1016/j.jcis.2017.12.058

Surface oxidation of single wall carbon nanohorns for the production of surfactant free water-based colloids

J Colloid Interface Sci. 2018 Mar 15:514:528-533. doi: 10.1016/j.jcis.2017.12.058. Epub 2017 Dec 22.

Authors

Filippo Agresti¹, Simona Barison², Alessia Famengo¹, Cesare Pagura¹, Laura Fedele³, Stefano Rossi³, Sergio Bobbo³, Marzio Rancan⁴, Monica Fabrizio¹

Affiliations

¹ Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), National Research Council of Italy (CNR), Corso Stati Uniti 4, Padova, Italy.
² Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), National Research Council of Italy (CNR), Corso Stati Uniti 4, Padova, Italy. Electronic address: simona.barison@cnr.it.
³ Institute of Construction Technologies (ITC), National Research Council of Italy (CNR), Corso Stati Uniti 4, Padova, Italy.
⁴ Institute of Condensed Matter Chemistry and Technologies for Energy (ICMATE), National Research Council of Italy (CNR), c/o Dept. Chemical Science, University of Padua, Via Marzolo 1, 35131 Padova, Italy.

PMID: 29289735
DOI: 10.1016/j.jcis.2017.12.058

Abstract

In this work, powders of Single Wall Carbon Nanohorns (SWCNHs), a typical hydrophobic material, were oxidized with concentrated HNO₃ with the aim of surface carboxylation and consequent improved hydrophilicity and dispersibility in polar solvents. Dynamic Light Scattering and ζ-potential measurements demonstrated that very stable colloidal suspensions of SWCNH in water were obtained in total absence of stabilizers. By properly optimizing the reaction parameters, the suspensions achieved stability even higher than colloids with similar composition but prepared with the use of surfactants. Surface damage and oxidation degree of SWCNHs were evaluated by SEM microscopy, Thermogravimetric Analysis, Residual Gas Analysis, XPS and UV-visible spectroscopy.

Keywords: Colloid; Oxidation; Single wall carbon nanohorn; Stability; Water.