The actuator functionality of electromechanical polypropylene films was studied using atomic force microscopy. The film carries a permanent electric charge and includes microbubbles as a result of two-dimensional stretching of the film. The thickness change of various film structures covered with electrodes was measured as a function of external voltage. The dependence was found to be nonlinear, the thickness change in the range 0.001%–0.1% of the total film thickness and affected by the internal charge density of the film. Applying a capacitor model including an air gap within the polymer layer enabled the determination of the Young’s modulus, the interfacial charge density and the actuator sensitivity of the studied structures.
Peltonen, J., Paajanen, M., & Lekkala, J. (2000). Determination of the actuator sensitivity of electromechanical polypropylene films by atomic force microscopy. Journal of Applied Physics, 88(8), 4789 - 4793. https://doi.org/10.1063/1.1290448