Publication

Abstract : Polyaniline is known for its good thermal stability, high electrical conductivity and corrosion resistance. Incorporating fillers like carbon black as secondary phases enhances these properties, making it available for electrical and electronics applications. Introducing these composites as nanofibers on an electrode overlay can be beneficial from electron mobility standpoint. Electrospinning is one of the commonly pursued methods for synthesizing nanofibers. However, it is difficult to electrospin polyaniline alone as it is insoluble in organic/inorganic solvents. Inorder to overcome this problem, polyaniline is blended with binder solutions like polyvinyl alcohol (PVA). But, the presence of an insulating carrier like PVA introduces a percolation threshold (threshold voltage beyond which a material starts behaving as a conductor) which can affect applications where high conductivity is required. The problem adds up when carbon black is introduced into the polyaniline matrix. Carbon black tends to create a solid gel when mixed with PVA resulting in a high viscosity solution which makes this blend not suitable for electrospinning. In the present chapter, highly conductive porous ( 70%) polyaniline-carbon black composite nanofiber mats were fabricated via electrospinning. The fiber mat was electrospun using polyvinyl alcohol as carrier solution which was later decomposed at  230 °C to get a complete conducting nanofiber network and did not result in any structural collapse. This heat treatment reduced the fiber diameter from  240 nm to  170 nm, increased surface pore size from 0.4±0.08 μm to 1.3±0.35 μm and the porosity of the mat increased from 40±1.2% to 75±2%. The removal of the carrier phase in the composite was confirmed by Fourier transform infrared spectroscopy. The spatial specific conductance measurements using scanning electrochemical microscopy showed that the presence of polyvinyl alcohol could introduce percolation threshold and removal of the same by heat treatment substantially reduced the percolation threshold and increased the fiber mat conductance. The heat-treated fibers showed four times increase in specific conductance values on removal of carrier phase from the fiber structure. The present chapter discusses the role of carbon black in polyaniline matrix, which can be beneficial as conductive electrode applications in electronic and photovoltaic storage devices. © 2013 by Nova Science Publishers, Inc. All rights reserved.