Analysis of Fractional-Order Models Of Polyaniline Doped Polyacrylonitrile Fibres Impedances’ (PAN/PANI)

Abstract

the paper describes the use of electrical impedance spectroscopy (eiS) for characterizing the impedance of polyaniline doped polyacrylonitrile fibres. The electrical impedance of fibres samples was measured by means of high impedance analyser and modeled by four types of models: Debye, cole-cole, Davidson-Cole and Havriliak-Negami. The fitting errors are presented for all model types. The model parameters are correlated with chemical substances additives and processing which were used during the fibres production. The presented results show that the fractional-order models reflect properly the impedance spectra of fibres samples.Electrical impedance spectroscopy (EIS) is widely used for measuring the electrical impedance of tested materials over a given range of frequencies 1 . It returns the complex impedance spectra in the frequency domain. EIS is used for characterising different types of substances and materials. Electrical impedance spectroscopy results play an important role in the modelling process of new and designed materials. Modelling the behaviour and response of materials is important for various reasons. Namely, prediction of standard and anomalous phenomena is possible by the use of model analysis and model-based simulation. Moreover, in many applications, the models allow to evaluate performance indexes and to adjust the structure or material's parameters so that responses obey design specifications and reference behaviours 2 .Textile materials (various clothing and technical fabrics) are made of polymeric, natural or chemical fibers, in particular synthetic ones. These fibers are mainly polymers with poor electroconductive properties (e.g., polyacrylonitrile fibers are dielectrics with a resistance of 10 11 Ω). Among textile materials there is a group of smart/ intelligent textiles that are sensitive to external stimuli such as stress, temperature, humidity, the intensity of the electromagnetic field or the presence of chemical substances. Under the influence of the above-mentioned external factors, the textile material changes its properties, e.g. volume, color or electrical conductivity 3,4 . The electrically conductive polymer fibers are of great importance 5 . Electroconductive fibers, depending on their resistance, can be used as electrical connections, sensors or electromagnetic field shielding materials. However, the mechanical properties of the electrically conductive fibers must allow their further processing to obtain a textile product.In this work, polyacrylonitrile-polyaniline fibers (PAN/PANI) were made. The polymer matrix for these fibers was polyacrylonitrile and admixture -an electrically conductive polymer -polyaniline. Polyaniline is an intensely tested material mainly due to its high electrical conductivity, low price and an easy method of obtaining. However, the biggest difficulty associated with its use is its low mechanical strength and processing problems. For this reason, the fibers were made from a mixture of polyaniline with fiber-forming polyacrylonitrile, which in this...

The Effect of Temperature on Electric Conductivity of Polyacrylonitrile-Polyaniline Fibers

“… Polyacrylonitrile fibers are characterized by a much more homogeneous structure and lower porosity in comparison to composite PAN/PANI fibers [35], [41].…”

Passive approximations of double‐exponent fractional‐order impedance functions

“…The three‐parameter H‐N model is given by where and β are fractional orders (dispersion coefficients) and τ is a characteristic time‐constant. The C‐C model and C‐D model are special two‐parameter cases of the H‐N model, as illustrated in Figure 1A 21 …”