Decoupled shear flexoelectric effects in polymers

The coupling between dielectric polarization and strain gradient, known as flexoelectricity, is a property of all dielectric materials. Flexoelectric coefficients are essential during applications. In order to increase the number of measurable flexoelectric coefficients, more experimental approaches are needed. In this work, circular terrace and column models are developed to generate shear strain gradients along radial and longitudinal directions to obtain the flexoelectric coefficients. Theoretical deduction, finite element method analyses, and experiments are applied to several polymeric specimens. The relationships between torque load and electric charge are then obtained, and the flexoelectric coefficients μ_φzρz and μ_φzzz are simultaneously obtained. This flexoelectric coefficient decoupling method is proved to be applicable to various polymeric materials. This work enhances the experimental methods of research on decoupled shear flexoelectric effects.