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.

Beads labelled using surface enhanced resonance Raman scattering (SERRS) are highly sensitive and specific tags, with potential applications in biological assays, including molecular diagnostics. The beads consist of a nucleus containing dye labelled silver-nanoparticle aggregates surrounded by a polymer core. The nuclei generate strong SERRS signals. To illustrate the coding advantage created by the sharp, molecularly specific SERRS signals, four specially designed SERRS dyes have been used as labels and three of these have been combined in a multiplex analysis. These dyes use specific groups such as benzotriazole and 8-hydroxyquinoline to improve binding to the surface of the silver particles. The aggregation state of the particles is held constant by the polymer core, this nucleus also contains many dye labels, yielding a very high Raman scattering intensity for each bead. To functionalise these beads for use in biological assays an outer polymer shell can be added, which allows the attachment of oligonucleotide probes. Oligonucleotide modified beads can then be used for detection of specific oligonucleotide targets. The specificity of SERRS will allow for the detection of multiple targets within a single assay.

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