This review presents a detailed survey of Dielectric Elastomer Actuators (DEAs) and their emerging role in medical applications. DEAs are distinguished by their flexibility, low weight, and excellent biocompatibility, making them well-suited for a wide range of medical devices. The review explores the fundamental electro-mechanical principles behind DEA operation, which enable their remarkable ability to replicate natural muscle movements. Key applications discussed include biomedical devices, rehabilitation systems, in-vivo implants, and wearable health monitors, where DEAs offer dynamic, lifelike movements and precise control. Their ability to provide highly flexible and responsive actuation is a major advantage in medical technologies. However, challenges persist, particularly in terms of material durability, the need for high-voltage activation, and the integration of DEAs with existing medical technologies. By synthesizing recent research and highlighting ongoing hurdles, this review emphasizes the transformative potential of DEAs, offering a comprehensive look at their current state and future impact on next-generation medical devices.

Dielectric elastomer actuators (DEAs) can be described as compliant capacitors formed by a dielectric elastomer film sandwiched between two electrodes. An applied voltage results in a compressive Maxwell stress, a thickness reduction and thus an expansion in the other dimensions. In order to favor large uni-axial deformations, it is predicted that DEAs ought to be constrained in the other direction. This can be achieved by reinforcing the DEA with unidirectional fibers. In this paper, the behavior of uni-axial fiber-reinforced DEAs is established and the proposed model innovates by taking into consideration the fiber properties such as their Young’s modulus and dimensions, and is characterized by transversely isotropic models. A novel fabrication process is then presented for reinforced DEAs by using 3D printed fibers with four different materials, namely Nylon, PETG, ABS and PLA, and different coverages of fibers are considered. Fiber reinforcement is shown to increase uni-axial strain up to 75% in the manufactured DEAs when compared to traditional DEAs. This behavior corresponds to the one predicted by the proposed model.

Dielectric elastomer actuators (DEAs) have gained significant attention due to their potential in soft robotics and adaptive structures. However, their performance is often limited by their in-plane strain distribution and limited mechanical stability. We introduce a novel design utilizing fiber reinforcement to address these challenges. The fiber reinforcement provides enhanced mechanical integrity and improved strain distribution, enabling efficient energy conversion and out-of-plane displacement. We discuss an analytical model and the fabrication process, including material selection, to realize fiber-reinforced DEAs. Numerical simulations and experimental results demonstrate the performance of the fiber-reinforced equibiaxial DEAs and characterize their displacement and force capabilities. Actuators with four and eight fibers are fabricated with 100 $\mathsf{\mu }$m and 200 $\mathsf{\mu }$m dielectric thicknesses. A maximal out-of-plane displacement of 500 $\mathsf{\mu }$m is reached, with a force of 0.18 N, showing promise for the development of haptic devices.

Dielectric elastomer actuators (DEAs) are a recent type of smart materials that show impressive performances as soft actuators, making them a promising technology for the development of implantable artificial muscles and soft robotic devices. Notably, they are explored as implants for the restoration of facial movements post paralysis. However, implementing DEAs that mimic natural muscles has been proven difficult, as DEAs provide in-plane expansion when actuated, while natural muscles contract upon stimulation. Multiple solutions can be found in literature, namely stack DEAs and fiber-reinforced DEAs. The fibers used for DEAs to achieve contractile motion rely on a fishnet design, where the angle between the fibers, the spacing, mechanical properties as well as the fiber dimensions can be set by establishing a fiber analytical model. Contraction has only been achieved with DEAs based on acrylic elastomer and pre-stretched with rigid frames, thus making them unsuitable as soft implants. This work introduces the first silicone-based, non-pre-stretched DEAs presenting in-plane contractile behavior by embedding such soft structured fiber sheets in the actuators. Fiber-reinforced DEAs were shown to achieve modest contractile strains, particularly with optimal fiber angles between 55^∘ and 65^∘, enhancing their ability to mimic muscle-like behavior. A peak occurs at approximately 60^∘, where the maximum contraction of −0.6% was achieved, resulting in a 3% error from the model. The low contractile strains of silicone-based DEAs indicate that further optimization is needed for real-world applications.