The thickness of an electrochemically active biofilm, its cell density, stability and transport properties, the kinetics of its formation and its robustness against variable environmental conditions are of central importance for the efficiency and the practical benefits of bioelectrochemical cells. The aim of this project is to develop a method for the in situ determination of the thickness and the shear stiffness of electrically active biofilms using acoustic torsional resonators.i The acoustic and the electrochemical properties shall be correlated to develop a physical-electrochemical biofilm model.
Key issues are:
A torsional resonator consists of a cylindrically shaped piezoelectric crystal, which is excited to a torsional vibration by electrodes on the side of the resonator. The resonant frequency is in the range of 50 kHz. The resonance frequency and bandwidth change when the resonator comes into contact with a sample. Using a viscoelastic model, these changes can be converted into a film thickness and an apparent stiffness of the film. The dotted line sketches the amplitude distribution of the shear wave.
Persons:
Philipp Sievers,
Dr. Arne Langhoff,
Prof. Diethelm Johannsmann
Link to the ElektroBak projects website.
Link to subproject B3 on the ElektroBak projects website.