Broadband Dielectric Spectroscopy in nano-(bio)-physics

F. Kremer, A. Serghei, J. R. Sangoro, M. Tres, E.U. Mapesa
2009 2009 IEEE Conference on Electrical Insulation and Dielectric Phenomena  
Broadband Dielectric Spectroscopy as one of the major tools in molecular physics, benefits from the extraordinary advantage that its sensitivity increases with decreasing thickness of a sample capacitor and hence with a decreasing amount of sample material. This enables one, for instance, to carry out broadband spectroscopic measurements on quasi-isolated polymer coils in nano-structured capacitor arrangements having thicknesses as small as 10 nm. It is demonstrated that for polymers like
more » ... c polystyrene (PS) or poly-2-vinyl-pyridine (P2VP), the dynamic glass transition can be measured for (averaged) sample thickness as small as ~ 2 nm in a wide spectral range (10 mHz to 10 MHz) and temperature interval (150 K to 350 K). No shift of the mean relaxation rate and no broadening of the relaxation time distribution function are found compared to the bulk liquid. Electrode polarization is a ubiquitous phenomenon that takes place at the interface between a metal and an ionic conductor. A quantitative theory is presented, which enables one to deduce from its characteristic frequency, temperature and concentration dependencies -by use of a novel formula -the bulk conductivity of the ion conducting liquid under study. It is shown that the electrical relaxation processes take place within a nanometric layer at the (ionic conductor/metal) interface.
doi:10.1109/ceidp.2009.5377717 fatcat:xdvvbqsq25dzjageg5vehbd2cm