Microfluidic electrokinetics PhD. Student: Anne Benneker Phone: +31-53-4892962 Thesis advisor: Prof. dr. ir. R.G.H. Lammertink E-mail: firstname.lastname@example.org Supervisor: Dr. P.A. Tsai URL: http://www.utwente.nl/tnw/sfi/ Research group: UT-SFI Research school: JMBC Supported by: ERC Period: July 2013-June 2017 • Introduction • In systems containing a charge selective medium (e.g. a membrane or a nanochannel) ion concentration polarization (ICP) is observed at the interface of the membrane. At intensive currents, ICP associates with an overlimitingcurrent (OLC) regime, in which the conductivity and de electric field near ion selective interfaces change by orders of magnitude, resulting in chaotic electrokinetic flows. Scientific understanding of this dynamic phenomena is crucial for the control of momentum and charge transport in these systems. Several theories and models are available for the description of this OLC behavior, but conclusive experimental verification is still lacking. • Figure 1: Typical micro/nanochannel configuration • Aim of research • In this research, local momentum transport induced by ICP at OLC is investigated experimentally near micro/nanochannel intersections. The transient behavior of the electrokinetic flow phenomena is typically studied (in this research) in a microfluidic device as is shown in Figure 1. Results will be used for conformation of theoretical predictions and a better understanding of the occurring OLC effect. • Approach • Flow visualization is an important tool in understanding fluid flow properties. Using charged and non-charged particles the fluid motion near the micro/nanochannel interface will be tracked for the establishment of flow profiles. Many interesting research questions will be investigated, such as the characteristics of lateral inhomogeneities on the onset of the instability, the correlation between vortex properties (dimension and intensity) and nanochannel/membrane and process conditions, and the influence of cross flow hydrodynamics.