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The evolving usefulness of organic conducting polymers, of metallic or semiconducting type, is primarily dependent on their mechanisms of electrical conduction and degradation. Understanding these mechanisms is crucial for improving the effi ciency and lifetime of technologies derived from this class of polymers. There is demand for a model that provides a vivid and more precise evaluation of the electrical conduction mechanism in these polymers – especially when they act as hosts to guest species, such as acid dopant ions and nanoparticles. If, for example, the motional behavior of a host–guest organic conducting polymer structure, as related to dynamic stability, is either asynchronous or synchronous, is this refl ected in the mechanism of electrical conduction and does it account for the pace of material’s degradation? Here, we demonstrate that the answer is affi rmative: asynchronous structural motions arising due to loosely bound or free guest species within the host polymer lead to anomalous electrical conduction mechanisms, increased fragility and short lifetime, at odds with the synchronous behavior.

Organic-inorganic hybrid materials are an upcoming class of materials that attract increasing research interest. In the present manuscript, we report on the combination of a particularly versatile organic matrix – the conductive polymer polyaniline (PAni) – with a special type of polyoxometalates (POMs), namely a lacunary Keggin anion, [AsW9O33]9–. Although the high application potential and the manifold structural motifs of POMs provide an almost infinite number of options for composite materials, up to now, only few POM-polymer combinations have been explored in more detail. Thus, we have investigated the interaction of PAni with the unique reactivity of [AsW9O33]9– that combines building-block facilities with the presence of a lone pair on the heteroatom. The resulting composite material was characterized with a wide spectrum of analytical techniques and the effect on the reaction conditions on the nanoscale structuring was investigated. Furthermore, the newly synthesized POM-PAni composites display a stable temperature-dependent resistivity that renders them promising for further applications.

We describe a rapid one-step, room temperature method to chemically synthesize bulk quantities of nanocomposites comprising specifically of manganese ferrite (MnFe2O4) and polyaniline (conductive form). Typically a chemical agent, for example ammonium peroxydisulfate, is used to start the polymerization of aniline in the presence of ferrites, and stirring of the reaction system for several hours is also very common. Our approach allows for the nanocomposites to be formed in less than thirty minutes without adding an external polymerization initiator/surfactant and applying any form of mechanical agitation. This process affords the possibility to grow thin films of polyaniline-MnFe2O4 directly on device substrates. Structural, thermal, magnetic and electrical studies did reveal significant chemical interactions between MnFe2O4 and polyaniline matrix. The nanocomposites are magnetic semiconductors with long rod-shaped structures of average diameter in the nanometer scale range and optical properties resembling that of conductive polyaniline. They exhibit a positive magnetoresistance across all temperature ranges with a minimum at around 250 K, corresponding to the temperature for their uniform-to-irregular transition in dynamic stability behavior and likewise coinciding with a minimum in their profile of electrical conduction mechanism (one-dimensional variable range hopping below 250 K) – these complementarities are important for hybrid spintronic applications., Swiss National Science Foundation SNSF PP002–114711/1; Portuguese Foundation for Science and Technology FCT PTDC/CTM/099489/2008 ISBN: 978-1-4398-7142-3