In this collaborative study, researchers from the Institute for Mechatronics in Mechanics and the Institute of Solids Process Engineering and Particle Technology at Hamburg University of Technology, as well as the Department of Microsystems Engineering at the University of Freiburg, present a novel methodology for using electrical impedance spectroscopy to analyze the electrical properties of dissolvable powders.
To address challenges posed by undefined geometries, powders were dissolved and applied as coatings on custom-designed Printed Circuit Board electrodes. Using sodium benzoate as a model material, the drying process was monitored in off-line measurements, revealing distinct transitions in electrical properties. Impedance and phase angle measurements effectively tracked moisture reduction during drying, while coating thickness and solution concentration also influenced conductivity. The study demonstrate the potential of this approach for industrial applications, such as fluidized bed spray granulation, by enabling real-time monitoring of drying states and provides an important step toward data-driven, sensor-based process understanding - a key building block for the next generation of smart reactors.
Maximilian Becker, Maike Orth, Anupam Kumar, Dennis Kähler, Matthias Kuhl, Stefan Heinrich, Thorsten A. Kern (2026). Impedance spectroscopy for multi-state analysis of dissolvable powders: Determining layer thickness and moisture content. Powder Technology 478, 122493.
