Affordable Access

deepdyve-link
Publisher Website

Separation and purification of nanoparticles in a single step.

Authors
  • Hollamby, Martin J
  • Eastoe, Julian
  • Chemelli, Angela
  • Glatter, Otto
  • Rogers, Sarah
  • Heenan, Richard K
  • Grillo, Isabelle
Type
Published Article
Journal
Langmuir
Publisher
American Chemical Society
Publication Date
May 18, 2010
Volume
26
Issue
10
Pages
6989–6994
Identifiers
DOI: 10.1021/la904225k
PMID: 20039604
Source
Medline
License
Unknown

Abstract

Reversed-micelle synthesis has been used to generate CTAB-stabilized gold (Au-NPs) and silver nanoparticles (Ag-NPs). By inducing a phase transition and subsequent separation of the background supporting microemulsion, it has been possible to extract and purify the NPs from the reaction medium. After addition of excess water, the NPs concentrate into an upper octane-rich phase, with impurities and reaction debris (in particular CTAB) partitioning into the water-rich lower phase. UV and (1)H NMR showed that 82% of the original mass of Au-NPs can be purified from the excess CTAB and other salt impurities. The concentrated and purified NPs can be dried down, by solvent removal, and then redispersed in octane. Using the complementary techniques small-angle neutron and X-ray scattering (SANS and SAXS), the structures of microemulsions both with and without nanoparticles prior to separation, and in both upper and lower phases after separation, have been elucidated. The approach has also been applied to the synthesis and recovery of silver nanoparticles, but on a larger scale. This new approach compares favorably with existing methods as it uses no additional organic solvents, has a low-energy demand, and requires no specialist surfactants. The new advance here is that by using a colloidal system to prepare and support the nanoparticles as a structured solvent, a simple soft purification method becomes accessible, which is otherwise impossible with a normal molecular solvent.

Report this publication

Statistics

Seen <100 times