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EPR spectroscopy was used to examine the magnetic properties of two enzymatically synthesized polyaniline (PANI) samples obtained in the presence of submicrometer-sized vesicles formed from sodium bis(2-ethylhexyl)sulfosuccinate (AOT) as templates. PANI-HRPC-AOT was synthesized with horseradish peroxidase isoenzyme C (HRPC) and hydrogen peroxide (H2O2) as oxidant while PANI-TvL-AOT was prepared with Trametes versicolor laccase (TvL) and dioxygen (O2) as oxidant. A commercial conductive sample of the emeraldine salt form of polyaniline (PANI-ES) was also used for comparison in order to correlate the experimental data obtained for PANI-HRPC-AOT and PANI-TvL-AOT with the properties of the well-characterized PANI-ES. It was shown that a model based on the concept of correlated polaronic bands could be applied for the interpretation of the EPR spectra of all three examined samples, although PANI-HRPC-AOT and PANI-TvL-AOT were significantly less conductive than PANI-ES. The magnetic properties of the PANI samples could be related to their conductivities, whereby a low conductivity was ascribed to decreased interchain spin interactions which were detectable from a splitting of the triplet spectrum at low temperatures (5-10 K). The obtained effective distance between the polyaniline chains is larger for enzymatically synthesized PANI than for PANI-ES, most likely mainly due to the presence of AOT which could not be removed completely during the work-up. AOT influences the chain conformation and the average chain-chain distance.

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The complementary application of the NMR inversion recovery measurements and the computer fitting of the overlapping spectral region is found to be a useful method for structural analysis of vulcanized natural rubber in the solid state. Since the linewidths in 13C‐NMR spectra of solids are relatively broad compared with the differences between chemical shifts, some weak signals are completely obscured in the resulting spectra. If the resonances have sufficiently different relaxation times, such as methyl and methylene carbons, it is possible to detect neighboring heavily overlapped signals by using the inversion recovery delay τ value at which the interfering strong resonance has null intensity. The 20 resonances observed in the spectra of crosslinked rubbers are tentatively assigned to the structural units formed during the vulcanization process. It is found that vulcanizates containing smaller amounts of sulfur (1 and 3%) show insignificant changes in the NMR spectra for curing times of 30 and 90 min. Structural modifications in rubbers cured with 10% sulfur continuously increase with the increasing curing time up to 120 min, indicating a significant loss in double bonds in the later stages of the reaction.

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