Click chemistry on solution-dispersed graphene and monolayer CVD graphene

Zhong Jin, Thomas P. McNicholas, Chih Jen Shih, Qing Hua Wang, Geraldine L.C. Paulus, Andrew J. Hilmer, Steven Shimizu, Michael S. Strano

Research output: Contribution to journalArticlepeer-review

170 Scopus citations


Graphene from two different preparative routes was successfully functionalized with 4-propargyloxybenzenediazonium tetrafluoroborate in order to study a subsequent attachment by click chemistry (1,3-dipolar azide-alkyne cycloaddition) of a short chain polyethylene glycol with terminal carboxylic end group (PEG-COOH). The reaction steps were studied by FTIR and Raman spectroscopies, as well as zeta-potential and surface tension measurements. In the first route, pristine graphene was surfactant dispersed from a stage controlled expanded graphite before reaction, resulting in colloidally stable dispersions after dialysis removal of the surfactant following the two functionalization steps. The chemistry was shown to increase the zeta-potential from -45.3 to -54.6 mV and increase the surface tension from 48.5 to 63.0 mN/m compared to those of the precursor solution. The magnitudes of the zeta-potential and the resulting solution concentration were shown to increase with grafting density up to 14.2 μg/mL. A colloidal stability model was used to estimate the maximum grafting density of the PEG-COOH groups yielding a value of 1 per 10 nm2. Raman mapping before and after the two-step functionalization suggests that edges and defects are preferentially reacted. In the second route, we investigated the same click chemistry functionalization on chemical vapor deposition (CVD) synthesized monolayer graphene films, which showed higher reactivity than solution-dispersed graphene. Because these methods do not originate with the more oxidized forms of graphene, the results point to new ways of more precisely controlling the chemistry of graphene.

Original languageEnglish (US)
Pages (from-to)3362-3370
Number of pages9
JournalChemistry of Materials
Issue number14
StatePublished - Jul 26 2011
Externally publishedYes


  • click chemistry
  • grapheme
  • surface functionalization

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry


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