Hybrid polyaniline/bentonite-vanadium(V) oxide nanocomposites

This work focuses on the preparation and properties of novel ternary composites generated from the redox polymerization of aniline inside the lamellar bentonite-vanadium(V) oxide (BV) matrix. These materials are stable in water and usual organic solvents, and their good electrical conductivity ensures potential applications as electrode modifiers, for analytical and sensor purposes. The incorporation of polyaniline (pani) into the BV matrices, leads to the decay of the charge transfer band at 450 nm and to the rise of a strong band around 650 nm, reflecting the reduction of VV sites, concomitant with the formation of polyaniline, in the emeraldine form. The modest expansion (∼2.5 A) observed in the pani intercalated composites, is consistent with the orientation of the polyaniline chains parallel with the interlamellar planes. On the other hand, the presence of intercalated polymer seems to stabilize the BV framework, minimizing the structural reorganization usually required for the insertion of lithium ions into the matrix. Interestingly, in small amounts, e.g. in BV(pani)0.7, polyaniline dramatically increases the conductivity and charge-capacity of the BV matrix; while, increasing amounts of polyaniline lead to an opposing effect