Flexoelectricity in non-oriented liquids

Flexoelectricity is a universal electromechanical effect in dielectric materials, describing strain gradient-induced electric polarization, of which, significant research has been performed for solid dielectrics and liquid crystals. Flexoelectricity of non-oriented liquids may have an impact on the research of bioelectronics, programmed droplets, energy harvesting and ionotronic devices, but it is not accessible for research due to a lack of theory and experimental approaches. In this work, flexoelectricity in non-oriented liquids is theoretically predicted and obtained by applying a shear strain gradient and the flexoelectric response of several types of liquids are demonstrated. Shear strain gradient of liquids is applied with a special-designed geometry and loaded by cyclic rotation from the chamber and the induced electric polarization is measured for flexoelectric coefficients. Experiments are designed and the shear flexoelectric response of non-oriented dielectric liquid materials are theoretically estimated and experimentally verified. This work opens the field of research for flexoelectricity in general non-oriented liquids and highlights the electromechanical properties of liquid materials.