Dielectric spectroscopy of blends of polyvinylalcohol and polypyrrole

Abstract

Polymeric blends composed of conducting polypyrrole chains dispersed in a matrix of polyvinylalcohol containing ferric chloride represent a class of materials whose electrical behavior is intermediary between those of insulating and conducting polymers. To investigate the transport and polarization characteristics of these films we examine in this work their dielectric relaxation spectrum in the frequency domain. A relaxation in frequency identified in the resistance–reactance diagram is followed as a function of the relative concentration of the two polymers, as different types of dopants are used to promote the conducting behavior of polypyrrole. We also analyze the change in the relative dc and ac contributions to the total conductivity of the samples as the amount of incorporated polypyrrole is increased.

Aggregation of methyl orange probed by electrical impedance spectroscopy

“…4) [20,22]. By adopting the constant phase element (CPE) approximation [12,13], we have fitted the impedance results obtained in the range of frequencies 1 Hz-1 MHz to those of an equivalent R//C CPE type of circuit response, as discussed above.…”

“…By applying an external electric field of varying frequency and using EIS techniques, we have been able to map the relaxation times τ rel characteristic of the electric dipoles present in the system and, in this manner, have obtained a better description of the processes of molecular reorientation [19,20] and of the corresponding evolution of the aggregate formation in the solution. Due to the initial polarization and subsequent reorientation of the polar groups in the medium, the reaction field induced in the sample will be out of phase relative to the excitation signal.…”

Investigation of structural, optical and electrical properties of a new cobalt phthalocyanine thin films with potential applications in perchlorate sensor

“…s dc is the conductivity of the plateau region and it is related to free charges available in the material [28,29]. In high frequency region, the conductance increases continuously.…”

Preparação e caracterização elétrica de sensores de metanol à base de nanocompósitos híbridos de polipirrol/nanopartículas metálicas

“…Por sua vez, os polímeros condutores vêm sendo constantemente aplicados nos últimos anos em dispositivos luminescentes, diodos emissores de luz, atuadores mecânicos do tipo músculos artificiais entre outros [6][7][8] , sendo o polipirrol um excelente sistema para tais implementações [9][10][11] . A síntese de compósitos híbridos do tipo metal-polímero condutor, por sua vez, possibilita com que se tenha uma interação sinergética entre as propriedades de ambos os sistemas interagentes, possibilitando com que a auto-montagem em escala nanométrica dê origem a estruturas em que se tem o completo recobrimento das partículas metálicas pelo polímero condutor, e consequentemente se obtenha elevação na área superficial das partículas distribuídas pela matriz, influenciando finalmente na sensibilidade da mesma.…”