Giant flexoelectric response via mechanical and material design in elastomers

Abstract

Strain gradient, a source of mechanical asymmetry in dielectrics, causes electric polarization, which we call flexoelectricity. Manipulating the strain gradient is fundamental in the study of flexoelectricity and its applications. This work describes a mechanical design approach to creating an elastic modulus gradient for the generation and enhancement of flexoelectricity. Furthermore, by combining material design and non-uniform geometric shape, theories and experiments have indicated enhanced flexoelectricity by one order of magnitude. In addition, the flexoelectric response increases with respect to the elastic modulus gradient, developing a new approach to manipulating flexoelectricity by mechanical design. The flexoelectric effect of this multi-configuration design is significantly improved compared to either method individually due to the enlarged equivalent dipole moment gradient created by manipulating the magnitude and density of the dipole moments. This work provides an approach to tuning flexoelectricity through the combination of mechanical and material design, further promoting flexoelectric-based applications in sensing, actuation, and energy harvesting.