Physikalische Chemie - Direktor: Prof. Dr. Martin Wolf
Host: K. Campen
Monday, September 10, 2018, 11:00 am
PC Seminar Room, G 2.06, Faradayweg 4
Prof. Dr. David Soares
Laboratory of Nanostructures and Interfaces, Department of Applied Physics, “Gleb Wataghin” Institute of Physics, University of Campinas, Brazil
The water-bridge phenomenon, a tool to probe interfacial water
A floating bridge can be formed spontaneously when high voltage (~106 V/m) is applied to polar fluids in two capillary tubes in contact and then separated. This bridge bends under its own weight, and allows to determine its Young’s modulus value. Two distinct structural regions form the bridge, a charged plastic conducting outer layer which shapes and supports the floating fluid structure, and an inner liquid cylinder, where fluid molecules flow. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates space charging in the interelectrode gap determining the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension.