The electrical behavior of surfactant added non-polar liquids is governed by the presence of charged inverse micelles. For surfactants like PIBS the transportation of charged inverse micelles from 0→V and from V→0 has been studied using transient current measurements1,2,3. The main contributions to these currents are due to drift and diffusion of charged inverse micelles. Now, after steady-state is reached in the polarizing step (0→ V1), the transition from V1→V2 is investigated with surfactant PIBS (OLOA 11k) in dodecane, which is relevant for the switching of colloidal particles in electronic inks. For low voltages (|V2|<10V) the current measurements upon switching from V1→ V2 are in good agreement with simulations of the Nernst-Planck-Poisson equations (see Fig. 1). The shape of the currents can be understood from dynamic space-charge effects related to the switching of charged inverse micelles from within the diffuse double layer at one electrode to the other electrode. The first part of the measured currents is typically also well understood for higher voltages. However, for increasing amplitude of the voltage V2 a peak in the measured currents occurs earlier than expected, which is related to electrohydrodynamic effects speeding up the switching of charged micelles.
Fig.1 Transient current measurement for voltages goingfromV1=15V toV2=-0.5, -1.5, -5, -15 and-50V. The measurements (dots) and simulations (lines) shows a good agreement atshort times and low voltages.
1. P.Kornilovitch and Jeon Yoocharn,Journalof Applied Physics,2011,109, 064509.
2. M.Z. Bazant, K. Thornton and A. Ajdari,Physicalreview E,2004,70, 021506.
3. F. Beuniset al. COCIS,2013,18, 129.
Manoj.Prasad@elis.ugent.be
