Gemini surfactants as efficient dispersants of multiwalled carbon nanotubes: Interplay of molecular parameters on nanotube dispersibility and debundling

• Type: Article in International Scientific Journal
• Date: 2019

Authors

Abreu, B (Author) FCUP; Rocha, J (Author) Other; Fernandes, RMF (Author) Other; Regev, O (Author) Other; Furo, I (Author) Other; Eduardo F Marques (Author) FCUP

Journal

Title: Journal of Colloid and Interface Science

Vol. 547

Pages: 69-77

ISSN: 0021-9797

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 27 Citations

Scopus - 29 Citations

Other information

Authenticus ID: P-00Q-DTH

DOI: 10.1016/j.jcis.2019.03.082

Abstract (EN): Surfactants have been widely employed to debundle, disperse and stabilize carbon nanotubes in aqueous solvents. Yet, a thorough understanding of the dispersing mechanisms at molecular level is still warranted. Herein, we investigated the influence of the molecular structure of gemini surfactants on the dispersibility of multiwalled carbon nanotubes (MWNTs). We used dicationic n-s-n gemini surfactants, varying n and s, the number of alkyl tail and alkyl spacer carbons, respectively; for comparisons, single-tailed surfactant homologues were also studied. Detailed curves of dispersed MWNT concentration vs. surfactant concentration were obtained through a stringently controlled experimental procedure, allowing for molecular insight. The gemini are found to be much more efficient dispersants than their single-tailed homologues, i.e. lower surfactant concentration is needed to attain the maximum dispersed MWNT concentration. In general, the spacer length has a comparatively higher influence on the dispersing efficiency than the tail length. Further, scanning electron microscopy imaging shows a sizeable degree of MWNT debundling by the gemini surfactants in the obtained dispersions. Our observations also point to an adsorption process that does not entail the formation of micelle-like aggregates on the nanotube surface, but rather coverage by individual molecules, among which the ones that seem to be able to adapt best to the nanotube surface provide the highest efficiency. These studies are relevant for the rational design and choice of optimal dispersants for carbon nanomaterials and other similarly water-insoluble materials.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9