Importance of dielectric constant in the development of stretchable electronics materials

Stretchable electronics require materials that maintain their electrical performance even under significant mechanical strain. The dielectric constant is important for figuring out device sensitivity, operating voltage, and energy density. However, there is extensive research on stretchable polymers, elastomers, energy harvesting devices, and composite dielectrics, and the dielectric constant, but data remain inconsistent and fragmented to predict materials and device design. This review examines the role of the dielectric constant in stretchable electronic materials, as well as measurement approaches and modelling strategies. It includes contributions to the key classes of materials, composite dielectrics, elastomers, and stretchable polymers and examines the relationships among materials, dielectrics, device sensitivity, operating voltage, and energy density as they are mechanically strained. Several studies have measured the dielectric constants of stretchable electronic materials. These studies demonstrate the variety of differences in dielectric constant that occur due to different conditions of the test or different compositions of the materials and indicate the need to have a more unified understanding of the structure-property relationships. However, limited open access data and the lack of standardised measurement methods make accurate analysis challenging and affect device performance. Solving these challenges through standardised measurement practices and the sharing of open datasets will play a crucial role in advancing the rational design of future stretchable, electronic, and energy-harvesting devices.