Multiscale Modeling and Theoretical Design of Dielectric Elastomers

Abstract

Dielectric elastomers (DEs) are a promising material for use in robotic, biomedical, energy, aerospace and automotive technologies. However, currently available DEs are limited by weak electromechanical coupling and our general understanding of DEs could improve. In this work, a multiscale model of dielectric elastomers is developed. At the molecular scale, an electrostatic response of a single DE monomer is assumed and, using statistical mechanics, the thermodynamics of a DE chain is investigated. This chain scale model leads to an important insight: the role of electrostatic torque on polymer chains in the electromechanical coupling of dielectric elastomers. This chain torque occurs because there is a connection between a chain’s end-to-end vector and its polarization. At the continuum-scale, this macromolecular phenomena manifests itself in the form of a deformation dependent susceptibility. Not only are novel modes of electromechanical coupling discovered, but also lessons learned from (standard) isotropic dielectric elastomers are then used to guide an in-depth analysis of the implicationsof designing and manufacturing anisotropic dielectric elastomers. The work in theoretical design reveals how the deformation and usable work derived from (anisotropic) dielectric elastomer actuators may be increased by as much as 75 - 100% relative to standard, isotropic dielectric elastomers.