Rheological properties and material characteristics of field-responsive fluids응답성 유체의 유변 물성과 재료 특성

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In this thesis, experimental studies on the field-responsive fluids were performed in terms of the development of novel materials and characterization of the rheological properties. The field-responsive fluids are representative smart materials having electric or magnetic field-dependent properties induced by the patterned structures in the external field. Among them, electrorheological (ER) and magnetorheological (MR) fluids can offer a potential applicability in development of a novel device as a fast, reversible mechanical-electrical interface. However, the performance of ER and MR fluids should be further improved along with the fundamental understanding of related mechanisms. Therefore, major objective of this thesis is placed in the understanding of the relation between the material properties and microscopic/rheological behavior of these fluids. As a novel ER material for the high temperature application, semiconductive polymeric particle suspension is prepared. In order to investigate the effects of the electrical properties of polymeric particles on the ER phenomena, conductivity of semiconductive poly(p-phenylene) particle is controlled. The dielectric behaviors of ER suspension revealed facilitated interfacial polarization for the suspension with intermediate conductivity of particle. These behaviors were closely related with the magnitude of dynamic yield stress, which showed a maximum and then decreased with increasing the conductivity of particles. Therefore, we established an optimum condition of particle conductivity showing the maximum ER activity. In order to promote the ER effect considerably, a novel multiphase dispersion system has been designed and investigated. Here the dispersed emulsion drop is introduced to the polyaniline particle suspension with optimum conductivity. The electrical conductivity of emulsion drop (Celeclor s45) was $10^2$ times higher than that of medium (silicone oil), so that this emulsion itself showed ER activity...
Advisors
Park, O-Okresearcher박오옥researcher
Description
한국과학기술원 : 화학공학과,
Publisher
한국과학기술원
Issue Date
2000
Identifier
157721/325007 / 000965391
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학공학과, 2000.2, [ xiii, 124 p. ]

Keywords

Viscoelasticity; Yield stress; Magnetorheological fluid; Electrorheological fluid; Dispersion stability; 분산안정성; 점탄성; 항복응력; 자기유변유체; 전기유변유체

URI
http://hdl.handle.net/10203/28833
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=157721&flag=dissertation
Appears in Collection
CBE-Theses_Ph.D.(박사논문)
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