EPR investigations of mesoscopic disorder in polypyrrole

Electron spin resonance experiments on polypyrrole films show that oxygen g as increases the asymmetry ratio (A/B) for the highly conducting sample syn thesized at -40 degreesC, decreases A/B (after an early increase) for the s ample synthesized at 0 degreesC, and has no effect on the lowest conductivi ty sample prepared at 20 degreesC. These results support a heterogeneous mo del for these materials with less disorder in samples synthesized at low te mperatures compared to those synthesized at high temperatures, and with oxy gen having different effects with different time scales in ordered and diso rdered regions.