Soft, tough, and fast polyacrylate dielectric elastomer for non-magnetic motor

Abstract

Dielectric elastomer actuators (DEAs) with large electrically-actuated strain can build light-weight and flexible non-magnetic motors. However, dielectric elastomers commonly used in the field of soft actuation suffer from high stiffness, low strength, and high driving field, severely limiting the DEA’s actuating performance. Here we design a new polyacrylate dielectric elastomer with optimized crosslinking network by rationally employing the difunctional macromolecular crosslinking agent. The proposed elastomer simultaneously possesses desirable modulus (~0.073 MPa), high toughness (elongation ~2400%), low mechanical loss (tan δm = 0.21@1 Hz, 20 °C), and satisfactory dielectric properties ($${\varepsilon }_{{{{{{\rm{r}}}}}}}$$ ε r = 5.75, tan δe = 0.0019 @1 kHz), and accordingly, large actuation strain (118% @ 70 MV m−1), high energy density (0.24 MJ m−3 @ 70 MV m−1), and rapid response (bandwidth above 100 Hz). Compared with VHBTM 4910, the non-magnetic motor made of our elastomer presents 15 times higher rotation speed. These findings offer a strategy to fabricate high-performance dielectric elastomers for soft actuators.

A processable, high-performance dielectric elastomer and multilayering process

“…There have been important advances in the development of DE materials, including polyacrylates with optimized cross-linking networks ( 13 ), bottle-brush polymers ( 6 ), interpenetrating networked elastomers ( 14 ), and high–dielectric constant elastomers ( 15 , 16 ). A bimodal-networked DE material was reported to suppress EMI without prestretching ( 8 ).…”

Flexible Electronics and Devices as Human–Machine Interfaces for Medical Robotics

“…In contrast to soft pneumatic actuators that demand gas supplements and tendon driven actuators that require motors, EAP actuators are activated directly through electrical signals. [486,487] However, the actuation stress, strain, and efficiency of EAPs are problematic (mainly weak) in applications to prosthetics, especially for ionic polymer actuators. [488] Likewise, dielectric elastomer actuators (DEAs) at human scale can only generate relatively low force (below 100 mN) but require a high working voltage (around 1000 kV) to operate.…”

Fabrication and actuation characterisation of a new UV curing acrylic dielectric elastomer

“…The monomer, photo-initiator and CN9021 were dispersed by ultrasound and stirred to form a homogeneous solution. The prepared mixed solution was poured into a home-made mould [14,21], and then the bubbles in the solution were removed by vacuuming for 15 min in the vacuum box. After being irradiated for 3 min by UV light, the mixed solution was cured into DE films of 1 mm.…”

“…High actuation voltage may cause electrical breakdown and electromechanical instability (EMI) of DEs [12,13]. Besides, high viscoelasticity of DE leads to low energy conversion efficiency, which is apparent in DEs such as VHB TM 4910 [14]. These defects mentioned above significantly limit the application of DEs.…”