Advances in Materials Physics and Chemistry, 2012, 2, 75-81 doi:10.4236/ampc.2012.22013 Published Online June 2012 (http://www.SciRP.org/journal/ampc) Synthesis and Electrical Properties of Polyaniline Composite with Silver Nanoparticles Safenaz M. Reda 1* , Sheikha M. Al-Ghannam 2 1 Chemistry Department, Faculty of Science, Benha University, Benha, Egypt 2 Chemistry Department, College of Girls for Science, University of Dammam, Dammam, KSA Email: safenazr@yahoo.com Received February 27, 2012; revised April 5, 2012; accepted April 15, 2012 ABSTRACT Polyaniline/silver (PANI/Ag) nanocomposite was prepared by chemical oxidative polymerization of aniline monomer in the presence of nitric acid. The formation of PANI/Ag nanocomposite was characterized by XRD, FTIR, TEM, UV-vis spectroscopy. The XRD patterns indicated that the crystalline phase of Ag is cubic with crystallite size of 93 nm. The TEM image shows that the Ag nanoparticles are well dispersed in the polyaniline matrix. Optical measurements show that the value of optical band gap of nanocomposite is lower than that of pure PANI. The DC-, AC-conductivities, dielectric permittivity (') and dielectric loss ('') of (PANI/Ag) nanocomposite and pure PANI have been measured in the temperature range from 303 to 723 K and frequency range from 10 to 10 3 kHz. The electrical conductivity of the (PANI/Ag) nanocomposite is higher than pure PANI. Temperature variation of frequency exponents in this blend sug- gests that AC-conductivity is attributed to correlated barrier hopping mechanism. At all frequencies, the ' value for (PANI/Ag) nanocomposite is higher than that for pure one. The higher dielectric constant of the PANI/Ag nanocompo- site indicates their better ability to store electric potential energy under the influence of alternative electric field. Keywords: Polyaniline/Silver (PANI/Ag) Nanocomposite; DC-Electrical Conductivity; AC-Electrical Conductivity; Dielectric Permittivity; Dielectric Loss 1. Introduction Polymers are generally insulators and to exhibit electrical conductivity they must possess, ordered conjugation with extended (pi) electrons and large carrier concentrations. Conjugated polymers are the organic compounds that have an extended (pi) orbital system and conjugated car- bon system [1]. Conductive polymer with polyaromatic backbone including polypyrrole, polythiophene, polyani- line, etc. has received a great deal of attention in the last two decades [2]. The conductivity of these conjugated polymers can be controlled by the process of doping which may be carried out through a chemical route, elec- trochemical route or photochemical route and is charac- terized by charge transfer from dopant to polymer or from polymer to dopant [1]. On doping these conjugated polymers show very high conductivity similar to metals. Therefore sometimes they are also called Synthetic Metals. They combine the electrical properties of metals with the advantage of polymers such as smaller weight, greater workability, resistance to corrosion and lower cost [1]. The most exciting applications of conductive polymers are in television sets, cellular telephones, automotive dashboard displays and artificial cockpit displays, Light emitting devices (LEDs), solar cells, lightweight batteries, light emitting diodes, polymer actuators, corrosion pro- tection agents, sensors and molecular electronic devices [1,2]. Amongst the family of conducting polymers poly- aniline (PANI) is one of the most promising electrically conducting polymers due to its unique electrical, electro- chemical properties, easy polymerization, high environ- mental stability and low cost of monomer [3]. Also, its wide applications in microelectronic devices, diodes, light weight batteries, sensors, super capacitors, microwave absorption, corrosion inhibition [3]. Moreover, PANI has attracted attention for various reasons such as high absor- ption coefficients in the visible part of the spectrum, high mobility of charge carriers and tremendous stability [1]. Also PANI is unique among conductive polymers in that its electrical properties could be reversibly controlled both by charge transfer doping and by protonation, which makes it a potential material for applications such as chemical and biological sensors, actuators, microelec- tronic devices, etc. [4]. PANI exists in a number of forms which totally differ in chemical and physical properties. The most conducting emeraldine salt has conductivity on * Present Address: Chemistry Department, College of Girls for Science, Dammam University, Dammam, Kingdom of Saudi Arabia. Copyright © 2012 SciRes. AMPC