My main current research interest concerns with the development of
a new experimental approach to measure the local dielectric response
of polymers and nano-composites materials with nano-metric resolution.
To achieve this objective I am currently developing a new tool that combines an Atomic Force Microscope (AFM) with a Lock-in amplifier. This approach allows measuring the dielectric interaction between the tip of the AFM and the surface of the sample. In this way it is possible to obtain maps of dielectric contrast as well as the dielectric loss spectrum at a single point of the sample surface. Several different approaches we developed during the last years. The excitation of the tip with a DC voltage, combined with a numerical model, allowed measuring quantitative dielectric maps of thin polymer films [JAP, 106, 024315 (2009), PRE, 81, 010801 (2010), Ultramicroscopy, 110, 634-638 (2010)]. Later on, AC voltage was used to excite the tip and the response was measured in both amplitude and frequency modulation working on air atmosphere as well as under ultra high vacuum. In this way, it was possible to image the polymer dynamics [APL, 96, 213110 (2010)] as well as to measure the dielectric spectra at different temperatures in the broadest frequency range obtained so far [Ultramicroscopy, 111, 1366-1369 (2011)]. Currently, I am trying to extend the frequency range up to six decades and also to improve the thermal stabilization of the sample. In addition, different theoretical models are being analysed in order to fully understand the physical meaning of the obtained data.
Words cloud made with the text content of all my articles until 2010.