nanoDielectric Spectroscopy

Dielectric relaxation (DR) in general and dielectric spectroscopy (DS) in particular have shown to be very useful, extended and versatile techniques to study dielectric materials and in particular polymers and other glass formers. DR studies allow obtaining valuable information about the molecular dynamics of the system under investigation at different length and time scales. However, the standard DR techniques have a fundamental limitation: they have no spatial resolution. To overcome this constrain we have been developing during the last years different novel approaches that allow both local and quantitative measurement of the dielectric permittivity of thin films by means of electrostatic force microscopy (EFM). Our goal is to measure the dielectric response as a function of frequency and temperature with the typical spatial resolution of standard atomic force microscopy (AFM). In this sense we have developed several approaches which are based on the measurement of different aspects of the tip-sample interaction. Thus, we are able to measure the dielectric response by means of the force gradient as well as the amplitude of the cantilever oscillation.

Part of this development was performed in collaboration with the Institute d`Electronique du Sud (IES), Université Montpellier (France) and the Institute de Mécanique des Fluides (IMFT), Université de Toulouse (France). We have also worked in collaboration with the Department of Physics, Northeastern University, Boston (USA).