Dresden 2026 – scientific programme

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O: Fachverband Oberflächenphysik

O 13: Solid-liquid interfaces: Reactions and electrochemistry I

O 13.5: Talk

Monday, March 9, 2026, 16:00–16:15, TRE/PHYS

Electrokinetic spectroscopy of ion dynamics near charged surfaces using modulated surface acoustic waves — •Ofer Manor, Li Yifan, and Sudeepthi Aremanda — Technion, Haifa, Israel

We use MHz-level frequency-modulated surface acoustic waves (SAWs) to study the dynamics of ions in the electrical double layer (EDL) to appear near the charged glass/electrolyte interface. The SAW travels in the solid; the EDL exists in the electrolyte; both phenomena are entangled through a field effect, a mechanical evanescent wave, which is invoked in the electrolyte by the SAW and vibrates ions in the EDL to result in the leakage of an electrical field off the glass/electrolyte interface. We show measured spectra of electrolyte comprising different types and concentrations of salts and salt mixtures. This is a spectroscopy of ion dynamics in isolated and unique EDLs.

EDLs are nanometer-thick clouds of ions that appear at the charged interface between a substrate and an electrolyte solution and determines its electrical properties. Ions migrate through the EDL within micro- to nano-seconds: These are the EDL relaxation-times for charging and discharging, which are a product of the EDL structure and ion species therein.

Ion relaxation-times similar to the SAW periodic time result in an ion electro-mechanical synchronization, which maximizes ion vibration and the leakage of electrical fields off the EDL. The leakage identifies ion relaxation-time spectra for different electrolytes and the presence of ions and the intrinsic rate by which they charge and discharge EDLs.

Keywords: electrical double layer; ion relaxation time; surface acoustic wave; electrolyte; glass/electrolyte interface