Synthesis and properties of polypyrrole vanadium oxide hybrid aerogels

Vanadium pentoxide/polypyrrole aerogel composites were synthesized by two sol-gel routes. The first utilized simultaneous polymerization of pyrrole and vanadyl alkoxide precursors; Hydrolysis of VO(OC3H7)(3) using pyrrole/water/acetone mixtures over a range of compositions yielded monolithic green-black gels. Supercritical drying yielded aerogels (150-257 m(2)/g, 0.1-0.2 g/cm(3)). These polypyrrole/V2O5 'nanocomposites' exhibited lower electrical conductivity with increased polypyrrole content. The second method involved oxide gel formation in the presence of a dispersion of preformed colloidal polypyrrole. SEM studies of the resulting 'microcomposites' aerogels (80-140 m(2)/g) show the presence of polypyrrole particles encapsulated in the fibrous V2O5 network. These materials exhibit conductivity equivalent to that of vanadium pentoxide. The interaction between polypyrrole and V2O5 in the materials was probed using infrared spectroscopy. (C) 1998 Elsevier Science B.V. All rights reserved.