Spectroscopy of Nanostructured Conducting Polymers

Nanostructured Conductive Polymers 2010 John Wiley Sons, Ltd 

Nowadays a promising way to control the bulk polymer properties, such as conductivity, processability, thermal, and mechanical stabihties, is through the organization of the polymeric chains on the nanometer scale [7-9]. The first approach used to achieve this goal was the synthesis of conducting polymers in cavities of porous hosts. Commonly named nanocomposites, these materials have two or more different components on the nanoscale, and can show catalytic, electronic, magnetic, and optical properties better than those of the individual phases. The basic reason for this synergism is still not fully understood, but it is considered that confinement and electrostatic interactions between the components play an important role. 

The host structure must provide an environment of restricted geometry, sometimes preventing the reticulation of the polymeric chains. Chains of poly(aniline), poly(pyrrole) and poly(thiophene) and others have been encapsulated by many forms of host [10-13] (see Table 8.1). Two routes are commonly used for this (i) the monomer is dissolved in an organic solvent (or in aqueous solution in its protonated form), and by diffusion and/or charge-exchange processes, the monomer is encapsulated in the cavities of a host, followed by oxidation with ammonium persulfate or another oxidant in situ polymerization), (ii) a host having oxidant ions, such as Cu(II) or Fe(III) is exposed to monomer vapors and then acid vapors [10-11]. 

Martin et al. [8,9] developed one of the best methods for synthesis of polymers with hosts, using porous polycarbonate membranes (track-etched membranes) and porous alumina. Track-etched membranes are available commercially (Poretics, Nuclepore, etc.) with various sizes of pores from 10 nm upwards and a density of approximately 10 pores cm [8,9]. The membranes of porous alumina are prepared electrochemically from Al foil, and can have pore densities of up to lO pores cm . Polymerization within 

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Spectroscopy of Nanostructured Conducting Polymers 343 Table 8.1 Hosts used for formation of nanostructured conducting polymers... 

This chapter aims to explore the major studies using AFM for conductive polymers, focusing on the application of images and force spectroscopy for nanostmctured films, nanostructures, and sensors. 

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