Frequency-Dependent Dielectric Polarizability of Nanocolloids and Polyelectrolytes in Electric Fields

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Image left: JGU, Mainz. Image right: Reproduced with permission from J. Electrochem. Soc., 166, B3194 (2019). Copyright 2019, The Electrochemical Society.

Being able to handle and manipulate large molecules or other nano-objects in a controlled manner is a central ingredient in many bio- and nanotechnological applications. One increasingly popular approach, e.g., in microfluidic setups, is to use dielectrophoresis. Here, the nano-objects are exposed to an alternating electric field, which polarizes them. Depending on the polarization, they can then be grabbed and moved around or trapped by an additional field. However, the mechanisms governing the polarization of the objects, which are typically immersed in a salt solution, are very complicated. Simulations allow to disentangle the different processes that contribute to the polarizability and to assess the influence of key factors such as AC frequency, salt concentration, or salt diffusivity.

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Principal Investigators

Jiajia Zhou, Friederike Schmid

Institute of Physics, Johannes Gutenberg University Mainz