Electrical characterization of in situ polymerized polyaniline thin films (original) (raw)

An Insight into Ionic Conductivity of Polyaniline Thin Films

Materials

The work addresses an issue of the conductivity phenomenon in conductive polymer thin films. Polyaniline was chosen as a broadly used and thoroughly investigated conductive polymer in order to test and show capabilities of the developed original approach based on impedance spectra analysis. A number of films of different thickness were deposited onto a Pt electrode surface and consequently investigated in aqueous solution containing perchloric acid as an electrolyte. The processes that occur in polyaniline film were studied by cyclic voltammetry, electrochemical quartz crystal microgravimetry (EQCM) and electrochemical impedance spectroscopy (EIS). The role of incorporated ions as charge carriers was investigated with respect to the control of the conductivity properties of the film. Along with detailed polyaniline behavior study, the work makes up a fundamental scientific impact on theoretical electrochemistry and electroanalytical techniques.

Electrical Conductivity of Polyaniline Thin Films

2010

We use infrared spectroscopy measurements to estimate the electrical conductivity of highly conductive polyaniline at different temperatures. The reflectance data were fitted to a model that includes a number of contributions to the electrical conductivity, such as Drude response of the free carriers, vibrational contributions, and interband transitions. We use classical models for these contributions and an exact model for the optical properties of thin films on the thick substrates. The results give the effective charge-carrier density and the transport lifetime of these charge carriers. The far infrared measurements will be compared to dc transport measurements.

Conductivity of Thin Polymer Films Containing Polyaniline

Molecular Crystals and Liquid Crystals, 2008

Thin polymer films containing polyaniline doped with several organic dopants were manufactured and their conductivity was measured. The effect of chloroform vapour on the composite film conductivity was examined. The possibility of fabricating polyaniline-based chemiresistors working as gas detectors was taken into consideration. Resistivity of polymeric films patterned by Solvent Assisted Micromolding was also studied. Furthermore, impedance spectroscopy measurements were performed of thin films of pure doped polyaniline and of its blend with an insulating polymer.

Optimization of Electrical and Optical Properties of Polyaniline for the Electronics Applications

An attempt has been made to investigate the electrical, optical and structural properties of conducting polymer Polyaniline (PANI). The Polyaniline were synthesized by oxidative polymerization. The Polyaniline films were synthesized using optimized concentration of monomer Aniline, Hydrochloric acid (HCL) a dopant and by using Ammonium Peroxidisulphate (APS) as an oxidant. The polymer was grown from aqueous solutions below the room temperature. The PANI films shows a good uniform surface morphology at 2 0 C, temperature maintained at constant temperature bath. The I-V characterization of PANI film shows ohmic behavior and we have achieved better conductivity of the films. PANI thin films were characterized by analyzing UV-Visible and FTIR spectroscopy. The study reveals that the thin film of Polyaniline provides a very good mechanical strength, environmental stability, uniformity in surface, and very high conductivity, which are desired for active layers in sensor, chemiresistors in gas sensing applications, an anode for OLED and P-type material in PN-junction diode etc.

Effect of annealing on electrical conductivity and morphology of polyaniline films

Journal of Applied Polymer Science, 2001

We report structure–property relationships of polyaniline emeraldine base (EB) films that were produced by combining different processing steps in various sequences. The effect of annealing and doping processes on the surface structure of the films was investigated by atomic force microscopy (AFM), and the corresponding changes to the chemical structure of the EB films were monitored by Fourier transform infrared spectroscopy. AFM results indicate that after doping polyaniline (EB) films with HCl, the root mean square (rms) roughness of the surface of EB film increased ∼ 46%. When the doped films were annealed at 180°C under a nitrogen atmosphere for 3 h, the rms roughness was essentially unchanged from that of the initial, undoped films. The electrical conductivity of the films also showed a significant dependence on the processing sequence. When the doped polyaniline (EB) films were annealed, no electrical conductivity was observed. When these films were redoped, only ∼ 6% of the initial conductivity could be recovered. In another processing sequence in which the polyaniline (EB) films were first annealed and then doped, the electrical conductivity was only ∼ 12% relative to the film that was doped immediately after being cast. From this work, a strategy to reduce the surface roughness of films made from electrically conducting polyaniline (EB) is proposed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3602–3610, 2001

A Study on The Conductivity of Polyaniline Polymers

IOP Conference Series: Materials Science and Engineering

Polyaniline (PANI) is a promising conducting material to be used in a variety of electronic applications ranging from sensors, through solar cells to touch screens. Enhancing the electrical characteristics of polyaniline by increasing the charge carriers, using doping materials, allows for using it as a good alternative for semiconductors in the fabrication of integrated circuits. Zinc sulfide (Zns) is considered one of the attractive doping materials that improve the electrical characteristics of polyaniline owing to the distinctive optical characteristics in the visible range. In this work, a practical study on the electrical properties of polyaniline doped with zinc sulfide is presented and compared with pure PANI. Different volume rates of doping are tested, experimentally, and the results are collected. Voltage-current characteristics and the activation energy levels are obtained for different temperatures. From the results, it has been observed that the conductivity increases by increasing the doping rate and inversely related to temperature. A low activation energy level and improved I-V characteristics are shown to be approachable by careful choice of doping rate. Polyaniline doped with zinc sulfide provides low cost conductors for integrated circuits industry.

Structure and electrical properties of the oriented polyaniline films

Journal of Applied Polymer Science, 1994

The structure of oriented polyaniline (PANI) films were characterized by elemental analysis, FTIR, XPS, SEM, and X-ray diffraction, and their electrical properties were measured as a function of the protonation state, elongation ratio, temperature, and applied pressure. A maximum conductivity at room temperature for oriented PANI films can be achieved up to 500 s/cm with conductivity anisotropy as high as 20 : 1. The temperature dependence of conductivity for both unoriented and oriented films at 77-300 K and applied pressure of 0-11.4 kbar is consistent with the 3-D variable-range hopping model; however, the hopping barrier of oriented films is one order magnitude lower than that of unoriented films. The mechanism of enhanced conductivity for oriented PANI films is discussed. 0 1994 John Wiley & Sons, Inc.

Impedance and voltammetric studies of electrogenerated polyaniline conducting films

Synthetic Metals, 1994

Polyaniline thin films were electrochemically synthesized from aniline in three acids: sulfuric, hydrochloric and perchloric. Cyclic voltammetry was used in the electrosynthesis, and the relationship of voltammetric parameters and the properties of the conductive form of the films were investigated. The main tool for film characterization was impedance spectroscopy. Semiautomated plotting of three-dimensional Argand diagrams with a potential parameter was used for synoptic view of the system and nonlinear least-square data fitting was used for rigorous treatment. Charge storage capacity, resistance and changes in constant phase element parameters were analyzed in relation to the use of the three acidic media.