EFFECTS OF ULTRA-HIGH PRESSURES (GREATER-THAN-3.6 GPA) ON THE ELECTRICAL-RESISTANCE OF POLYANILINE BY IN-SITU FT-IR STUDIES

Electrical resistance measurements and FT-IR spectroscopy of polyanili ne were studied in situ under ultra-high pressures rated by a diamond anvil cell (DAC). The electrical resistance of polyaniline decreased a s the pressure increased, exhibiting polaron conductor characteristics . Minimum electrical resistance was observed at 3.6 GPa, about three o rders of magnitude smaller than that at 1.0 GPa. Changes in electrical resistance were reversible when the pressure was below 3.6 GPa. In si tu FT-IR results showed that irreversible chemical changes of the quin oid units in polyaniline molecular chains took place when the pressure exceeded 3.6 GPa, giving rise to a huge increase in electrical resist ance. (C) 1997 Elsevier Science B.V.