Electromagnetic and Electrical Properties of Coated Cotton Fabric with Barium Ferrite Doped Polyaniline Film Aysun Cireli Aks  it, 1 Nurhan Onar, 1 M. Faruk Ebeoglugil, 2 Isil Birlik, 2 Erdal Celik, 2 Ismail Ozdemir, 2 1 Textile Engineering Department, Faculty of Engineering, Dokuz Eylul University, Bornova 35100, Izmir, Turkey 2 Material and Metallurgy Engineering Department, Faculty of Engineering, Dokuz Eylul University, Buca, 35160, Izmir, Turkey Received 9 June 2008; accepted 3 December 2008 DOI 10.1002/app.29856 Published online 19 March 2009 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: In this study, we aimed to produce fabrics with microwave absorbing properties in broad band. For this purpose, the cotton fabrics were coated with polyani- line (PAni) by using chemical oxidative polymerization method. Firstly, the type of protonic acid used, the poly- merization time, the type and concentration of dopant, and the number of coating layer were varied as parame- ters. The effect of these parameters on resistance values of coated fabrics was investigated. We determined the most appropriate process conditions to provide the lowest re- sistance values. Secondly, the fabric was coated with PAni by adding barium ferrite powder as filler with different ratios. Morphological properties, electrical, and electro- magnetic properties of coated fabrics were determined. As a result, we obtained 350 X of the minimum resistance val- ues of coated fabric using 1M HCl, 0.5M aniline and 0.5M ammonium persulphate by chemical oxidative polymeriza- tion method for totally 4 h of polymerization time. The results of electromagnetic parameters showed that the absorption values of the fabric coated PAni was average 48% in the frequency range of 6–14 GHz. It was concluded that microwave absorber for a textile material can be suc- cessfully produced by this process. V V C 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 358–366, 2009 Key words: conducting polymers; coatings; monomers INTRODUCTION Conductive polymers show the electrical properties due to their conjugated double bonded chain struc- tures. 1 In recent years, electrically conductive poly- mers have been investigated for various industrial applications, including rechargeable batteries, elec- trochromic ’smart windows, composite structures, and electrodes. 2 p-electron conjugate polymers are polythiophene, polyaniline and polypyrrole etc. Among these polymers, PAni widely attracts inter- ests because of the resistance to environmental, ther- mal and chemical action, unique electrochemical property, reversibility in the doping/dedoping pro- cess, ready availability of raw materials, and sim- plicity and low cost of synthesis. Therefore, it was the first commercially produced polyconjugated polymer. 3–6 Nonetheless, its industrial application has some drawbacks, such as poor processibility and poor mechanical properties. Improvement of me- chanical properties could be accomplished by form- ing composites of PAni with conventional nonconductive polymers or textile substrates. 5 There are various methods to prepare PAni coated fabrics such as electrochemical polymerization, 7,8 chemical polymerization, 9,10 block or graft polymerization, 11,12 plasma polymerization. 6 To prepare the conductive composite fabrics, many scientists have focused on chemical oxidative polymerization, because this method does not require the destruction of the sub- strate and provides reasonably good conductivity. Furthermore, chemical oxidative polymerization is expected to be one of the most convenient methods, because it is a relatively simple and easy method to control the conductivity by maintaining the high strength of substrate fabric. 13 Electrically conductive textiles can be used as electromagnetic interference (EMI) shielding materials for personal computers and home electronic devices, flooring and ceiling materials, heating elements, deelectrifying cloths, dissipation of electrostatic charge, microwave absorber, radar cross section reducing protective fab- rics for stealth technology. 5,14 Many studies were performed to investigate the electromagnetic wave absorption properties of conductive polymer coated fabrics, but the microwave absorbing properties of magnetic powder doped conductive polymer coated fabrics was not studied beforehand. Journal of Applied Polymer Science, Vol. 113, 358–366 (2009) V V C 2009 Wiley Periodicals, Inc. Correspondence to: A. C. Aks  it (aysun.cireli@deu.edu.tr). Contract grant sponsor: The Scientific and Technological Research Council, Turkey (TUBITAK).