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Polar-molecules-driven enhanced colloidal electrostatic interactions and their applications in achieving high active electrorheological materials.
- Source :
- Journal of Materials Research; Feb2008, Vol. 23 Issue 2, p27-27, 1p
- Publication Year :
- 2008
-
Abstract
- We have fabricated a class of colloidal electrorheological (ER) fluids, in which suspended TiO<subscript>2</subscript> particles were synthesized by a sol-gel method and modified by 1,4-butyrolactone molecules with a permanent molecular dipole moment of 4.524 D. Compared with pure TiO<subscript>2</subscript> ER fluids, the quasi-static yield stress of the polar- molecules-modified ER fluid is enhanced as high as 48.1 kPa when subjected to an external electric field of 5 kV/mm. Also, it possesses other attractive characters such as low current density (<14 µA/cm2) and low sedimentation. Based on a Green's function method, we present a first-principles approach to investigate colloidal electrostatic interactions. Excellent agreement between experiment and theory has been shown for the enhancement ratio of quasi-static yield stress, which quantitatively reveals that enough polar molecules oriented within the field-directed gap between the colloidal particles can unexpectedly enhance the interactions, thus yielding the unusual enhancement. This shows a promising and flexible direction for achieving more highly active ER materials. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 08842914
- Volume :
- 23
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Journal of Materials Research
- Publication Type :
- Academic Journal
- Accession number :
- 30038024
- Full Text :
- https://doi.org/10.1557/JMR.2008.0057