https://doi.org/10.1140/epje/i2006-10007-3
Regular Article
Surface-functionalized nanoparticles with liquid-like behavior: The role of the constituent components
1
Department of Materials Science and Engineering, Cornell University, 14853, Ithaca, NY, USA
2
School of Chemical and Biomolecular Engineering, Cornell University, 14853, Ithaca, NY, USA
3
Department of Physics, University of Ioannina, Greece
4
Biomedical Research Institute (BRI)-FORTH, Ioannina, Greece
5
Department of Materials Science, FORTH-IESL, P.O. Box 1527, 71110, Heraklion, Crete, Greece
6
Max Planck Institute for Polymer Research, P.O. Box 3148, Mainz, Germany
* e-mail: fytas@iesl.forth.gr
Received:
11
January
2006
Accepted:
24
April
2006
Published online:
17
May
2006
Ionically modified silica nanoparticles with large counter anions (sulfonate, isostearate) at two silica volume fractions (13 and 27%) form a viscous fluid and a glass but not crystalline solids. Dielectric spectroscopy, Brillouin scattering and shear rheometry were employed to investigate these new nanoparticle-based fluids. The glass transition temperature and hence the local dynamics are governed by the large counter anions, whereas the flow properties can be controlled by the spatial correlation between the nanoparticles, e.g. by tuning the volume fraction of hard cores and local interactions between segments in the soft corona. Liquid-like ordering of the cores was revealed by X-ray scattering and found to influence significantly the macroscopic flow properties of these salts.
PACS: 89.75.-k Complex systems – / 83.10.Tv Structural and phase changes – / 62.25.+g Mechanical properties of nanoscale materials –
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2006