Bidisperse Electrorheological Fluids Using Hydrolyzed Styrene-Acrylonitrile Copolymer Particles: Synergistic Effect of Mixed Particle Size
| Autor: | Jung-Bae Jun, Seong-Yong Uhm, Kyung-Do Suh, Seong-Heun Cho |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Materials science
Dispersity Nanotechnology Surfaces and Interfaces Condensed Matter Physics Styrene Electrorheological fluid chemistry.chemical_compound Hydrolysis chemistry Chemical engineering Polymerization Electrochemistry Copolymer General Materials Science Particle size Acrylonitrile Spectroscopy |
| Zdroj: | Langmuir. 20:2429-2434 |
| ISSN: | 1520-5827 0743-7463 |
| DOI: | 10.1021/la030248c |
| Popis: | Monodisperse micron-sized styrene-acrylonitrile copolymer (SAN) particles with three different sizes (about 5, 10, and 15 microm) were prepared by a two-step seeded polymerization and used for a study of bidisperse electrorheological (ER) suspensions. The effect of the particle size and the size-mixing fraction on ER properties was studied with varying the size of these monodisperse copolymer particles. When the two particle sizes were mixed, the suspension generally showed a decrease in the shear yield stress, reaching a minimum value. However, a bidisperse ER suspension of large particles containing a small fraction of fine particles showed an interesting synergy effect of size mixing on ER response, giving enhanced yield stresses over the other size-mixing fractions. This synergistic ER suspension also showed a great increase in the viscoelastic property. The current density of suspensions was maximum at the synergistic bidisperse suspension. This synergy effect in a particular bidisperse suspension was investigated in view of the structure model consideration and was concluded to be due to a close packing and a peculiar structural ordering at an optimum size ratio and mixing fraction. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|