Thesis presented July 1^st, 2003

Abstract:
This work deals with an innovating experimental technique, 1/f noise measurements, in order to investigate conducting properties of conducting blends made of polyaniline (PANI) and insulating matrix of polymethyl methacrylate (PMMA). In the first part, an accurate description of the experimental setup is given. The influence of the sample shape, the position of electrical contacts and the measurement technique (2 or 4 probes) on the noise amplitude is discussed. Then, we show that organic conducting blends PANI-PMMA exhibit a 1/f noise whose amplitude S_R, as a function of concentration and resistance R, follows the percolation scaling laws with critical exponents κ=2.19 and ω=1.15. The influence of defects is tested by introducing intentional cut in the conducting network of PANI. The stronger sensibility of S_R, as compared to R, is evidenced experimentally and by numerical simulation.

Keywords:
electronic conducting polymers, conducting polymer blends, electronic transport, 1/f noise, disordered systems, electrical percolation

On-line thesis. ​