Carbon nanoparticle surface functionalisation: converting negatively charged sulfonate to positively charged sulfonamide

John D Watkins, R Lawrence, James E Taylor, Steven D Bull, G W Nelson, J S Foord, Daniel Wolverson, Liza Rassaei, N D M Evans, S A Gascon, Frank Marken

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

The surface functionalities of commercial sulfonate-modified carbon nanoparticles (ca. 9-18 nm diameter, Emperor 2000) have been converted from negatively charged to positively charged via sulfonylchloride formation followed by reaction with amines to give suphonamides. With ethylenediamine, the resulting positively charged carbon nanoparticles exhibit water solubility (in the absence of added electrolyte), a positive zeta-potential, and the ability to assemble into insoluble porous carbon films via layer-by-layer deposition employing alternating positive and negative carbon nanoparticles. Sulfonamide-functionalised carbon nanoparticles are characterised by Raman, AFM, XPS, and voltammetric methods. Stable thin film deposits are formed on 3 mm diameter glassy carbon electrodes and cyclic voltammetry is used to characterise capacitive background currents and the adsorption of the negatively charged redox probe indigo carmine. The Langmuirian binding constant K = 4000 mol(-1) dm(3) is estimated and the number of positively charged binding sites per particle determined as a function of pH.
Original languageEnglish
Pages (from-to)4872-4878
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume12
Issue number18
DOIs
Publication statusPublished - May 2010

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