This title appears in the Scientific Report :
2011
Please use the identifier:
http://dx.doi.org/10.1021/la103096n in citations.
Interactions between block copolymers and single-walled carbon nanotubes in aqueous solutions: a small-angle neutron scattering study
Interactions between block copolymers and single-walled carbon nanotubes in aqueous solutions: a small-angle neutron scattering study
The amphiphilic copolymers of the Pluronic family are known to be excellent dispersants for single-walled carbon nanotubes (SWCNT) in water, especially F108 and F127, which have rather long end-blocks of poly(ethylene oxide) (PEO). In this study, the structure of the CNT/polymer hybrid formed in wat...
Saved in:
Personal Name(s): | Granite, M. |
---|---|
Radulescu, A. / Pyckhout-Hintzen, W. / Cohen, Y. | |
Contributing Institute: |
Neutronenstreuung; JCNS-1 JCNS; JCNS Neutronenstreuung; ICS-1 Streumethoden; PGI-4 Streumethoden; JCNS-2 |
Published in: | Langmuir, 27 (2011) S. 751 - 759 |
Imprint: |
Washington, DC
ACS Publ.
2011
|
Physical Description: |
751 - 759 |
PubMed ID: |
21155544 |
DOI: |
10.1021/la103096n |
Document Type: |
Journal Article |
Research Program: |
Großgeräte für die Forschung mit Photonen, Neutronen und Ionen (PNI) BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung |
Series Title: |
Langmuir
27 |
Subject (ZB): | |
Publikationsportal JuSER |
The amphiphilic copolymers of the Pluronic family are known to be excellent dispersants for single-walled carbon nanotubes (SWCNT) in water, especially F108 and F127, which have rather long end-blocks of poly(ethylene oxide) (PEO). In this study, the structure of the CNT/polymer hybrid formed in water is evaluated by measurements of small-angle neutron scattering (SANS) with contrast variation, as supported by cryo-transmission electron microscopy (cryo-TEM) imaging. The homogeneous, stable, inklike dispersions exhibited very small isolated bundles of carbon nanotubes in cryo-TEM images. SANS experiments were conducted at different D(2)O/H(2)O content of the dispersing solvent. The data for both systems showed surprisingly minimal intensity values at 70% D(2)O solvent composition, which is much higher than the expected value of 17% D(2)O that is based on the scattering length density (SLD) of PEO. At this near match point, the data exhibited a q(-1) power law relation of intensity to the scattering vector (q), indicating rodlike entities. Two models are evaluated, as extensions to Pederson's block copolymer micelles models. One is loosely adsorbed polymer chains on a rodlike CNT bundle. In the other, the hydrophobic block is considered to form a continuous hydrated shell on the CNT surface, whereas the hydrophilic blocks emanate into the solvent. Both models were found to fit the experimental data reasonably well. The model fit required special considerations of the tight association of water molecules around PEO chains and slight isotopic selectivity. |