274034 Galvanostatic Measurements of Double Layer Formation in Doped Nonpolar Liquids

Monday, October 29, 2012: 2:35 PM
408 (Convention Center )
Benjamin Yezer, Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA, Dennis C. Prieve, Dept. of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA and Paul Sides, Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA

Galvanostatic Measurements of Double Layer Formation in Doped Nonpolar Liquids

Ben Yezer, Paul J Sides, and Dennis C Prieve          

Department of Chemical Engineering

Carnegie Mellon University

Pittsburgh, PA 15213

           

Amphiphilic surfactants are often added to nonpolar liquids to electrostatically stabilize particle suspensions in nonpolar media.  The surfactant molecules form reverse micelles a few of which can acquire charges by exchanging a proton during Brownian collisions.  These charged micelles then serve as charge carriers in nonpolar media and facilitate surface charges on solid particles.  Previous work1,2,3 has studied the formation of the diffuse counterion cloud when current is passed through doped nonpolar fluids held between parallel plate electrodes.  In past experiments, the transient current response to a constant applied voltage is measured.  This work introduces a galvanostatic method in which a potential is measured in response to a constant current through 10 μm thick solutions of OLOA 11000 in dodecane.  One advantage of constant current is the easy determination of the dielectric constant of the fluid.  Other fluid properties including the conductivity and total number of charge carriers are calculated from the transient potential response to a constant current.  A corresponding model describes the migration of charge carriers in the cell as diffuse clouds of charged micelles accumulate at either electrode, leading to a better understanding of the dynamics of charge carriers in nonpolar fluids. 1D. C. Prieve, J. D. Hoggard, R. Fu, P. J. Sides, and R. Bethesa, Langmuir 24, 1120 (2008) 2P. Kornilovitch, Y. Jeon, J. Appl. Phys. 109, 064509 (2011) 3F. Strubbe, A. R. M. Verschueren, L. J. M. Schlangen, F. Beunis, K. Neyts, J. Colloid Interface Sci. 300, 396 (2006)

 


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