Programmable, UV-Printable Dielectric Elastomers Actuate at Low Voltage without Prestretch and Supporting Frames

Abstract

Dielectric elastomers are soft and perfect insulator polymers able to produce large strains with high energy density under the effect of applied high voltage. However, their use in practical applications is hindered by the need for high voltage to actuate. Also, they need prestretching between rigid frames to produce out-of-plane shape changes, which may reduce their lifetime. Here, we synthesized a set of elastomers with high permittivity (from 20 to reach 60 at 10 3 Hz), controllable thermal properties (T g vary from −15 to −50 °C), and good mechanical properties (Young's modulus values between 0.48 and 0.2 MPa at 20% strain). Due to the high permittivity, an actuator made of the material was able to respond to a low voltage of 700 V and produce a 6.5% area strain for more than 10 000 cycles. Moreover, the elastomers were found to produce giant free-end bending displacements with prespecified bending direction (bend to the side of the positive electrode) under a low electric field, which we called programmable dielectric elastomers (PDE). Besides the aforementioned characteristics and performance, the formulated elastomers are suitable for UV-based three-dimensional (3D) printing. The printability of the elastomers allows fabricating programmable complex geometries to produce high deformations under relatively low electric fields.

Near-Zero Hysteresis Ionic Conductive Elastomers with Long-Term Stability for Sensing Applications

“…The elastomer formulation was obtained according to our last work . Briefly, an HPA monomer was mixed with DEG with 2 wt %.…”

“…Other photocurable resin components, a photoinitiator (diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide) and a light absorber (2,5-bis (5- tert -butyl-benzoxazol-2-yl) thiophene) were added to allow the printability of the formulations. The amount of both the photoinitiator and the light absorber was fixed in all formulations to 1 wt % for the photoinitiator and 0.05 g/100 mL for the light absorber after studying their effect on the printing process . The whole mixtures were placed in an amber glass bottle and put under magnetic stirring for 6 hours until a very clear homogeneous solution was obtained.…”

“…The elastomers are obtained by mixing highly stable polar dielectric elastomer monomers with hydrophobic polar ionic liquid. Dielectric elastomer formulations have been developed from previous work 30 by the polymerization of a lowmolecular-weight monomer (hydroxypropyl acrylate (HPA)) with diethylene glycol (DEG) as a cross-linker. In an open environment, these elastomers showed unique dielectric properties and long-term stability.…”

From Amorphous Silicones to Si-Containing Highly Ordered Polymers: Some Romanian Contributions in the Field

“…By incorporating carbon black [81] or carbon nanotubes within the PDMS matrix, stretchable electrodes were obtained, several conductivity performances of these being showed in Figure 5d. However, silicones suffer from low value of dielectric permittivity, requiring relatively high electric fields (E > 100 MV/m) on the electrodes for actuation [83][84][85][86]. Therefore, significant efforts are being made to improve this parameter.…”

“…However, silicones suffer from low value of dielectric permittivity, requiring relatively high electric fields (E > 100 MV/m) on the electrodes for actuation [83][84][85][86]. Therefore, significant efforts are being made to improve this parameter.…”