Low frequency raman modes in polypyrrole polymers

Abstract

Low frequency Raman scattering from fractal vibrational modes in polypyrrole is investigated. The polypyrrole was prepared by the chemical and electrochemical method, and the polypyrrole obtained was characterized by the infrared spectrum and X-ray diffraction. The experimental results show the broad band distribution between 30 and 140 cm −1 and the Raman peak at 65,77,116 cm −1 for exciting line with 5145 Å were observed. According to the fractal theory, we point out for the first time that the low frequency Raman spectra may be from localized fractal vibrational mode in polypyrrole molecule chian with the intensity of the Raman light scattering expressed as a function of frequency shift, fractal and spectral dimensions. The fraction dimension is estimated according to the experimental data. The Raman spectra are well explained in terms of a fraction description of localized vibrations.