Sequence isomerization of dielectric elastomers toward high performances in electrostrain, elastic energy storage, and energy harvesting

Abstract

Dielectric elastomers (DEs) have emerged as promising candidates for actuators, capacitor and generators, but suffer from low dielectric constant and inferior energy density. In addition, the mechanism remians confused, which can be solved by molecular dynamics simulations. However, the traditional coarse-grained molecular dynamics (CGMD) simulations cannot study the electromechanical coupling effect of DEs due to the lack of Coulomb forces, limiting the structural design of DEs toward high performance. In this work, we study the dielectric response of DEs using CGMD simulations with charged model for the first time. An interesting phenomenon is observed: Head-to-head isomer configuration reduces the chain dipole moment, but improves actuated planar area strain (S_p) by 45% and electromechanical energy density by 378%. The mechanism is the improvement of polarization due to enhanced dipole alignment in network strands under an applied electric field. Additionally, the sequence isomerism significantly accelerates the response rate and reveals a previously unreported scaling law—S_p=a*l g⁡(time)+b. Moreover, sequence isomerism leads to substantial improvements in charge density, discharge density, discharge efficiency, and maximum polarization under high-frequency electric fields, with increases of 66%, 162%, 58%, and 72%, respectively. Those performances of isomer are insensitive to electric field frequency and stress due to the quick dielectric response, demonstrating a promising potential in elastic energy storage. which is emerging as a promising candidate for next-generation high-performance capacitor. Furthermore, sequence isomerization enhances electrostatic potential energy by 85% and confers excellent cycling stability, thereby extending the applicability in energy harvesting systems. This work provides a novel strategy for the design of multifunctional DEs and a new method for studying the dielectric response of DEs. In the future, the CGMD simulations with charged model can be developed and applied to design novel DEs, such as dielectric liquid crystal elastomers and intrinsically elastic ferroelectric materials.