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Voltage-induced ion motion in conducting polymers (CPs) and the associated stress that evolves play an important role in determining the performance and lifetime of devices fabricated from these materials. In this work, a multi-beam optical stress sensor (MOSS) coupled with potential cycling was used to study films of polypyrrole (pPy) doped with indigo carmine (IC), a redox-active anion. We observe different magnitudes of stress in these films in different electrolytes (NaCl vs. HCl) due to the pH-dependent redox activity of IC. These results indicate that the redox activity of a dopant introduces an additional mode by which stress develops in films of CPs, which in turn could impact device performance.

Voltage-induced ion motion in conducting polymers (CPs) and the associated stress that evolves play an important role in determining the performance and lifetime of devices fabricated from these materials. In this work, a multi-beam optical stress sensor (MOSS) coupled with potential cycling was used to study films of polypyrrole (pPy) doped with indigo carmine (IC), a redox-active anion. We observe different magnitudes of stress in these films in different electrolytes (NaCl vs. HCl) due to the pH-dependent redox activity of IC. These results indicate that the redox activity of a dopant introduces an additional mode by which stress develops in films of CPs, which in turn could impact device performance.