Effect of electrode/polymer interface properties on electromechanical responses of polymer sensing units

Abstract

The difference of mechanical properties between metal electrode and polymer leads to deformation, damage and friction of electrode/polymer interface, which affect the electromechanical responses of polymer sensing units. In this paper, the normal, tangential loading and friction induced electromechanical responses of Cu/ polydimethylsiloxane (PDMS) interfaces under different geometrical parameters and loading velocities (V) have been studied experimentally and numerically. The polarization model considering flexoelectric effect, interface damage and friction effect is proposed. The results show that tangential loading and voltage U increase with increasing of interface area and V; the first extreme value of U (-200∼+200 mV) are mainly related to flexoelectric effect (strain gradient), the second extreme values of U (60–1100 mV) are affected by interface damage. The normal loading induced U are generated by interface damage. The friction induced U (-200∼-2700 mV) is related to relative friction distance and effective contact area. Theoretical analysis shows that, the flexoelectric coefficients are 10⁻¹¹∼10⁻¹⁰ C·m⁻¹, the interface damage induced voltage is 4424.63 ± 433.12 V·m⁻², the friction induced voltage is 17.54 + 391.43 L_c (V·m⁻¹) (L_c is the compression distance). The research can contribute to the development of electrode/polymer sensing unit.