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Polyaniline films prepared via the camphorsulphonic acid (CSA)m-cresol solution processing route have been synthesized with doping levels in the range of 10-90%. The electrical conductivity of these films has been measured as a function of temperature between 10 and 300 K. At a doping level of 30% the onset of metallic transport is observed, and at 60% the films are found to exhibit metallic transport down to 135 K, and have a maximum room-temperature conductivity of 300 ± 30 S cm −1 . The results are modelled in terms of a heterogeneous model of fluctuation induced tunnelling (FIT) and metallic transport.

Conductive polyaniline (PANi) films have been prepared via a new route comprising 2-acrylamido-2-methyl-1-propanesulphonic acid (AMPSA) as both the protonating acid and the solvating group, and dichloroacetic acid (DCA) as a solvent. The AMPSA content was varied so that between 30 and 100% of the nitrogen sites on polyaniline could be protonated. The temperature dependence of the conductivity of the films was measured between 15 and 300 K. Above 75-115 K, depending upon the protonation level, a negative temperature coefficient was observed. At 240-260 K a new transition was observed, essentially independent of the protonation level, above which the negative temperature dependency becomes much stronger. The conductivity data were fitted using a simple model employed previously for films of polyaniline camphorsulphonate, and comparisons made between the two systems. Differential scanning calorimetry measurements on a series of films showed an endothermic transition centred at 240-254 K, whose magnitude is dependent upon the AMPSA content. This thermal transition is ascribed to increased motion in the AMPSA anions when heated to above the transition temperature. The AMPSA anion may be considered to behave as a side chain ionically bonded to the PANi backbone, whose particular structure will affect the intrachain molecular dynamics, and hence electrical transport properties of the bulk polymer. The observed thermal transition correlates well with the new transition seen in the conductivity data. It was possible to draw films of uniaxially both at room temperature and at 363 K. The room temperature conductivity along the stretch direction was increased to a maximum value of for a film drawn at 363 K, compared to for an undrawn sample. The films are compared to previous results obtained with polyaniline films protonated with 10-camphorsulphonic acid (CSA).

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