Perspectives for new dielectric elastomers with improved electromechanical actuation performance: Composites versus blends

BACKGROUND: This work presents a comparison between composites and blends as two alternative approaches for the development of new dielectric elastomers offering superior electromechanical properties at lower driving electric fields. Silicone and polyurethane based dielectric elastomers were modified by either making particulate composites with high-permittivity ceramic fillers or by blending with different polymeric phases. RESULTS: Both foregoing and new data are taken under review. Experimental observations are compared and discussed to assess which one of the aforementioned approaches might be more generally preferable. Due to a consequent worsening of the mechanical properties, pure composite architectures yielded only limited results. While with the blend approach both an increase of the dielectric permittivity and an unexpected reduction of the tensile elastic modulus were observed, leading to an overall increase of the electromechanical response. CONCLUSION: The blending approach permitted to obtain a new dielectric elastomer with improved electromechanical properties by simply combining two low dielectric constant polymers. This is the first time such a type of result is reported. This study indicates that formulating all-polymeric compounds may represent a very promising route for obtaining new dielectric elastomers with improved actuation performance.