Abstract
Giant electrorheological (GER) fluids are a kind of smart material typically consisting of dispersed phase, continuous phase and additives. The capability of quick reaction to the application of an external electric field enables the GER fluid to vary its rheological behaviors instantaneously. In this thesis research, a historical overview of both electrorheological (ER) fluids and GER fluids developments are presented, along with their potential applications. The ER mechanisms with the associated ER physical properties are described with an emphasis on the GER effect with its corresponding rheological characteristics and critical parameters. The various ER materials applied in the recent studies are briefly reviewed and compared with their pros and cons. The main objective of this study is to systemically investigate the role of the continuous phase or additive in the GER fluids. Diester was chosen as the dispersing medium in the fluid, and the variation in its structure, particularly alkyl chain length and branch structure, had an impact on the GER performance and suspension stability. The experimental result indicated that the GER fluid prepared by long branched diester presented a superior GER behavior and dispersion stability. Non-ionic surfactant was selected as an ‘activator’ that was intentionally added to the GER fluid. The rheological and electrorheological responses, permeability, and anti-sedimentation property of the constituted GER fluid are researched. It was found that the GER properties of the fluid can be enhanced with the addition of a proper amount of sorbitan surfactant.
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