The potential energy of a pair of polystyrene spheres in alternating electric fields

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The drastic change in the viscosity of electrorheological (ER) fluids when an external electric field is applied has intrigued scientists from many different fields including engineering, chemistry, and physics for over half a century. It has been generally understood that the microscopic attractive forces between induced dipole moments of the suspended particles have important effects on macroscopic fluid properties. Great effort has been given recently to maximizing the strength of the attractive forces between the particles in ER fluids to achieve practical fluids, and important progress has been made. In the preliminary work presented here, we focus on trying to ... continued below

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10 p.

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Lin, S.; Fraden, S. & Hu, Y. April 1, 1995.

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The drastic change in the viscosity of electrorheological (ER) fluids when an external electric field is applied has intrigued scientists from many different fields including engineering, chemistry, and physics for over half a century. It has been generally understood that the microscopic attractive forces between induced dipole moments of the suspended particles have important effects on macroscopic fluid properties. Great effort has been given recently to maximizing the strength of the attractive forces between the particles in ER fluids to achieve practical fluids, and important progress has been made. In the preliminary work presented here, we focus on trying to understand the strength of the microscopic interactions between colloidal particles in alternating electric fields. The system used is a model system of aqueous suspensions of monodisperse polystyrene spheres. By using digital microscopy techniques to measure the inter-particle separations between two spheres at thousands of different times and at several different field strengths, we have been able to determine the probability density function P(r) for the separation distance r between the two particle centers. We begin this paper with a theoretical discussion in which the contributions of electrostatic repulsion, electric-field-induced dipole interaction, and van der Waals attraction to the pair potential are first considered. A probability density function for the distance between a pair of particles is then obtained from the pair potential using equilibrium statistical mechanics. The theoretical discussion is followed by a detailed description of the experimental apparatus - one that allows us to isolate pairs of polystyrene spheres in an essentially two-dimensional geometry by restricting the particles to a narrow gap between parallel glass plates. Finally, we examine the results of our experiments and compare our findings with theoretical predictions.

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10 p.

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OSTI as DE96000735

Medium: P; Size: 10 p.

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  • 208. American Chemical Society (ACS) national meeting, Washington, DC (United States), 21-26 Aug 1994

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  • Other: DE96000735
  • Report No.: DOE/ER/45522--2
  • Report No.: CONF-940813--43
  • Grant Number: FG02-94ER45522
  • Office of Scientific & Technical Information Report Number: 110712
  • Archival Resource Key: ark:/67531/metadc622702

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Office of Scientific & Technical Information Technical Reports

Reports, articles and other documents harvested from the Office of Scientific and Technical Information.

Office of Scientific and Technical Information (OSTI) is the Department of Energy (DOE) office that collects, preserves, and disseminates DOE-sponsored research and development (R&D) results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions.

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  • April 1, 1995

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  • June 16, 2015, 7:43 a.m.

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  • April 6, 2017, 7:13 p.m.

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Lin, S.; Fraden, S. & Hu, Y. The potential energy of a pair of polystyrene spheres in alternating electric fields, article, April 1, 1995; United States. (digital.library.unt.edu/ark:/67531/metadc622702/: accessed April 22, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.