High electrochemical stability of meso-Ni-salen based conducting polymer manifested by potential-driven reversible changes in viscoelastic and nanomechanical properties

Abstract

The potential-driven counter ion ingress and egress effect on viscoelasticity and nanomechanics of the poly(meso-Ni-SaldMe) film was examined. This effect was characterized by a new approach using two complementary operando techniques, vis., electrochemical piezoelectric microgravimetry (EC-PM) at the electrochemical quartz crystal microbalance (EQCM) and atomic force microscopy in the PeakForce Quantitative Nanomechanical Mapping mode run under electrochemical conditions (EC-PFQNM AFM). The EC-PM and EC-PFQNM AFM experiments showed that changes in viscoelastic and nanomechanical behavior of the poly(meso-Ni-SaldMe) film, caused by counter ions doping and dedoping in the course of polymer charging and discharging, were repeatable. In that way, we demonstrated that the film high stability under these electrochemical conditions resulted from reversibility of processes occurring in both bulk and surface of the poly(meso-Ni-SaldMe) film. This is why the polymer is very much suitable for application as an electrode material for electrochemical devices.