Principle : The dielectric spectroscopy is the tool for frequency analysis is the most reliable to put in evidence the phenomena of relaxations and conductions that happen at the microscopic scale in a polymer insulator.
This technique consists of placing a dielectric between two electrodes, to apply a sinusoidal voltage of fixed frequency to the terminals of the two electrodes and measure the impedance result and the phase shift of the induced current. the configuration is that of a capacitor with two electrodes are concentric cylindrical.
Interest/Objective:
In addition to fundamental studies of the dielectric behavior and electrical polymers, dielectric spectroscopy provides information that is relevant to the sectors using the polymer as a dielectric material. thus, fields of applications as diverse as electrical engineering, power electronics, microelectronics, nanoelectronics, biology, and pharmaceuticals are concerned. this experimental technique allows you to give practical information and direct relating to :
- The electrical insulating properties of amorphous polymers which are used traditionally for cable insulation in the ranges of frequency from mhz to mhz as well as for passivation layers in electronic devices modern, such as microchips ;
- The reliability of polymers in the presence of water for applications of electrical insulation used in transformers and alternators ;
- A follow-up of the state of degradation of insulation polymer-based, used in transformers, following a process of aging or electrical stresses, mechanical, thermal or thermo-mechanical ;
- The electrical performance of a polymer before its integration in an electronic device, in particular when it is used as a material with low permittivity in the application of the for very large scale integration (or vlsi for very-large-scale integration) ;
- The structural states of the polymer before and after its glass transition.