Assembly of acid-functionalized single-walled carbon nanotubes at oil/water interfaces

  • Feng T
  • Hoagland D
  • Russell T
  • 37

    Readers

    Mendeley users who have this article in their library.
  • 21

    Citations

    Citations of this article.

Abstract

The efficient segregation of water-soluble, acid-functionalized, single-walled carbon nanotubes (SWCNTs) at the oil/water interface was induced by dissolving low-molecular-weight amine-terminated polystyrene (PS-NH2) in the oil phase. Salt-bridge interactions between carboxylic acid groups of SWCNTs and amine groups of PS drove the assembly of SWCNTs at the interface, monitored by pendant drop tensiometry and laser scanning confocal microscopy. The impact of PS end-group functionality, PS and SWCNT concentrations, and the degree of SWCNT acid modification on the interfacial activity was assessed, and a sharp drop in interfacial tension was observed above a critical SWCNT concentration. Interfacial tensions were low enough to support stable oil/water emulsions. Further experiments, including potentiometric titrations and the replacement of SWCNTs by other carboxyl-containing species, demonstrated that the interfacial tension drop reflects the loss of SWCNT charge as the pH falls near/below the intrinsic carboxyl dissociation constant; species lacking multivalent carboxylic acid groups are inactive. The trapped SWCNTs appear to be neither ordered nor oriented.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Authors

  • Tao Feng

  • David A. Hoagland

  • Thomas P. Russell

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free