Novel DEA with organically modified silicone elastomer for permittivity enhancement

Abstract

Dielectric elastomer actuators (DEA) based on an organically modified silicone elastomer are introduced. The elastomer carries fluorinated sidegroups in the polysiloxane molecular chain and is synthesized from precursors which all are fluorinated. A fluorinated silicone oil is added in consecutive concentration steps as a softening agent. The electric properties of the modified silicone elastomers in terms of the permittivity, specific conductivity and electric breakdown field strength were investigated and compared with those of the unmodified silicone elastomer as the reference material. Moreover, the mechanical characteristics like Young's modulus in tensile and compressional load as well as the storage and loss modulus in shear load were studied. The permittivity of the modified silicone is enhanced by 80 % compared to the unmodified silicone elastomer. No strong alteration of the specific conductivity occurs. The electric breakdown field strength is comparable to t hat of the reference material. Simultaneously, the Young's modulus is decreased by the softening agent. Actuation measurements on model actuators show, that the actuation strain of the best materials surmounts that of the unmodified reference material by a factor of up to 5. The modified silicone elastomer materials can also be used for dielectric elastomer sensors and generators

The Current State of Silicone-Based Dielectric Elastomer Transducers

“…Commercial fluorosilicones were investigated early on by Pelrine et al but were shown to exhibit high leakage currents . Later, Böse et al prepared a home‐made system using trifluoropropyl‐functional divinylpolydimethylsiloxane, cross‐linked into an elastomer and mixed with fluorinated silicone oil, to create very soft silicone elastomers ( Y = 0.07 MPa at 45 wt% oil) with enhanced dielectric permittivity of up to ε' = 5.4. The actuation strain was improved by a factor of five using 40 or 45 wt% fluorinated silicone oil, though the leakage current was not stated.…”

Polar Elastomers as Novel Materials for Electromechanical Actuator Applications

“…Along the same lines, Böse et al used the vinyl end‐functionalized polysiloxane with trifluoropropyl side‐groups, P5 (Scheme d) and formed an interconnected network with PDMS using a hydrosilylation reaction. A material containing about 45 wt% of polar polysiloxane showed a ε′ = 5.5, a strain at break as high as 400%, and a maximum actuation strain of 7.5% at 14 V µm −1 . A further increase in the polar fraction of the elastomer resulted in difficult to handle, very soft films.…”

Advances in Polymeric Materials for Electromechanical Devices

“…Blending silicones with conductive or highly dielectric polymeric fillers affords an alternative approach to increasing permittivity . For example, Carpi and coworkers blended polydimethylsiloxane rubber with 1–6 wt% of conductive poly(3‐hexylthiophene) (PHT) .…”