Preparation, characterization and electrical conduction mechanism of polyaniline/ordered mesoporous silica composites

In this work, we have shown the preparation of polyaniline (PANI) and mesoporous ordered silica (SBA-15) composites. PANI/SBA-15 composites with different weight ratios were prepared in order to evaluate the electrical conduction mechanism. The analysis of the differential activation energy was carried out for composites, allowing the classification of the variable range hopping as one dimensional for the composites. The hopping parameter as a function of the sample mass ratio indicates that the insertion of aniline into the mesopores improves its intrinsic conductivity. A fibrilar morphology of the conducting PANI is formed by a controlled amount of the added polymer into SBA-15. It was confirmed by SEM and TEM analysis that the composites prepared with different PANI contents have different morphologies, indicating that the amount of polyaniline is crucial to obtain distinct morphologies. SAXS, NAI, TEM and SEM show that SBA-15 maintains its structure even after the polymerization process and the polymer is dispersed on the inorganic matrix. The parameters determined by the investigation of variable range hopping conduction by the differential activation energy method show that the PANI produced in these composites have higher electrical conductivity than pure PANI, possibly due to the improvement of the interparticle, interchain and intrachain processes for the charge transport, which are intimately related to the polymer morphology, fact coherent with SEM and TEM data.

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► PANI/SBA-15 using DBSA produces composites with high thermal stability.
► PANI fibers are formed increasing the PANI content in the composites.
► The hopping parameter indicates that the incorporation of PANI into the mesoporous channels of SBA-15 improves its intrinsic conductivity.