Separated-structured all-organic dielectric elastomer with large actuation strain under ultra-low voltage and high mechanical strength

We report the design and preparation of a separated-structured all-organic dielectric elastomer (DE) with large actuation strain under ultra-low voltage and high mechanical strength. Based on the protonic-conductivity mechanism of gelatin, a novel organic conductive filler with high dielectric constant and low elastic modulus was prepared by mixing gelatin and glycerol (GG). The separated structured DE was prepared by spraying a solution of GG into the multiple layers of thermoplastic polyurethane elastomer (TPU) nonwoven fabric by electrospinning, followed by hot pressing under vacuum. The densely packed TPU nonwoven fabric not only ensures the good mechanical strength of GG/TPU DE, but also separates GG filler and stops the formation of the GG continuous phase, preventing the formation of a conducting path under an exerted electric field. The novel GG filler considerably increases the dielectric constant and decreases the elastic modulus of the GG/TPU DE. As a result, the as-prepared DE exhibits good mechanical strength and 5.2% actuation strain at a very low electric field (0.5 kV mm^-1). To the best of our knowledge, the required electric field for the same actuation strain is the lowest compared to other DE reported in the literature. Because all components in this composite are organic and biocompatible, this study offers a new method for preparing a DE with large actuation strain at low electric fields for its application in biological and medical fields, in which a low electric field is required.