Papers by Keyword: Dielectric Elastomer

Abstract: The electromechanical performances of dielectric elastomers were investigated after the incorporation of the confined permittivity enhancing fillers in bacteria cellulose (BC) into polydimethylsiloxane (PDMS) films. The purpose of this study is to investigate the capability of BC as a confinement matrix for the permittivity enhancing fillers to overcome the low relative permittivity and at the same time to increase the softness of the PDMS films. The metal oxide and silicone oil were confined in BC before being physically mixed with PDMS at different percentages. The results showed that the confined TiO2-BC increased the relative permittivity and at the same time maintained the softness of the PDMS films to some extent. In addition to that, by adding confined silicone oil-BC into the PDMS films, this PDMS based dielectric elastomer (DE) becomes even softer.

Abstract: The recent developments in dielectric elastomers (DE) are spectacular. Currently, a DE as an actuator, 0.15 g of acrylic sandwiching SWCNT electrodes, is capable of lifting a weight of 8 kg by more than 1 mm at a speed of 88 msec. In the near future, DE motors could be used to drive electric vehicles. Moreover, the DE can be used as a high-efficiency sensor with the same structure. With a diameter of 20 mm and a thickness of 0.5 mm, it can accurately measure pressure from several kg to 150 kg. In addition, reversing this DE actuator (DEA) movement also enables high-efficiency power generation. In other words, when the DEA is stretched or pushed, it generates electric power. Single wall nanotubes (SWCNTs) were used as an electrode, and an acrylic DE power generation cartridge with a diameter of 80 mm was used. When the center of the DE power generation cartridge is pushed by about 15 mm, a power of 33.6 mJ is generated. Using these two DE cartridges, it was possible to charge a secondary battery through a DC converter. In addition to this power generator, practical research and development of power generation using wave power, wind power, waste heat, and fluids (ocean currents, water currents, etc.) is progressing. In this paper, we have described state-of-the-art DEAs, DE generators (including the case that the power generated locally by microgenerators are consumed locally), and DE sensors and explained their usefulness.

Abstract: Dielectric elastomer actuator (DEA) is a compact device that consists of stretchable electrodes and elastomers. This device is energy efficient in performance and holds great promise in the development of soft actuators. DEAs performance relies significantly on the mechanical properties of its elastomers. This present study focuses on evaluating the soft material made of Sylgard 184 as the elastomers for DEAs. Sylgard 184 is a silicone elastomer that comes with two main parts (elastomers and its curing agent). A specific mixing ratio between elastomers and curing agent is essential to produce solid and reliable silicone elastomer. The recommended ratio for the elastomer solution was ten parts for the elastomers and one part for the curing agent (10:1). Producing softer elastomers was possible by reducing the curing agent. However, the performance of the material was unknown. We performed a series of cyclic tensile tests to understand the mechanical characteristic of the elastomer made of Sylgard 184. The result shows that reducing the curing agent did not have a significant effect on its cyclic performance. Furthermore, the use of a 30:1 ratio in the application of DEAs and deformable linear actuator indicates stable performance for both devices.

Abstract: Dielectric elastomer (DE) technology are used in several applications for example generator, sensor and actuator. One of the major factors that limits the DE performance is premature electrical breakdown. Compositing is the example that have been reported to increase the breakdown strength. In this study polydimethylsiloxane (PDMS) film will be incorporated with two different fillers which are titanium dioxide (TiO₂) and zinc oxide (ZnO). Both metal oxides will be calcined up to 300°C before they are added to the PDMS elastomer as fillers. The results show that the calcined TiO₂ and ZnO that incorporated in PDMS films show significant increase of breakdown strengths. Meanwhile, the calcined TiO₂ PDMS film give higher breakdown strength as comparison to the calcined ZnO counterpart.

Abstract: The dielectric elastomer (DE) has the advantages of large deformation ability, fast response speed, low price and high energy density. Therefore, DE has great prospects as artificial muscle and flexible robot. The purpose of the research is to clarify the mechanical behavior for acrylate dielectric elastomer by tensile test, fatigue test and viscoelasticity measurement.

Abstract: The emerging field of soft robots offers the prospective of applying soft actuators as artificial muscles, replacing traditional actuators based on hard materials. Dielectric elastomers (DE), one class of electro-active polymers, represents an attractive technology for the realization of mechatronic actuators, due to their light weight, high energy efficiency and scalability. This work aims at investigating and characterizing a novel design of membrane DE in-plane actuator by magnetic mechanism. A nonlinear dynamic model of the dielectric elastomer actuator (DEA) is established and corresponding material parameters are identified. Natural frequency and response speed of DEAs are studied. It demonstrates that larger stretch and higher response speed can be realized by the proposed DEA.

Abstract: The combination of elastic natural rubber (NR) and conductive graphene were assessed for such improved electromechanical properties that are promising material in an actuator applications. For this work, dielectric elastomer composite films were prepared with varied graphene contents. These films were fabricated by solution casting method. The morphology along with electrical and mechanical properties, and specifically the electrostrictive coefficient, were studied. The electrostrictive behavior was determined from electric field induced strain, observed with a photonic displacement apparatus in the film thickness direction. It is shown that the electrostrictive coefficient for the NR/Graphene composite has already raised over 3.7 times compared to the neat natural rubber by the reason of an interfacial polarization. The surface between NR matrix and graphene filler generates the larger permittivity. Meanwhile, the Young's modulus was quite invariant. Consequently, the enlarging of the electrostrictive coefficient under low electric field of the NR/Graphene composites is representing a potentially good actuation response base on the electrostriction phenomena.

Abstract: This paper presents a review of some of the applications for artificial muscle and several material of artificial muscle. We focus attention on the polymer material artificial muscle, which responds to electrical stimulation with a significant change in shape or size. Through our research on a variety of materials and the analysis of the mechanical properties of muscle movement, finally we designed the artificial muscle device the imitation of muscles stretching device. This article describes the structure and performance of the device.

Abstract: Electroactive polymer transducers have many features that are desirable for various devices. An especially attractive type of electroactive polymer is dielectric elastomer (DE). Our recent progress is a DE actuator having only 0.1 g of DE that lifted a weight of 2 kg using carbon system electrodes. We also developed a ribbon form DE actuator having a sensor function that can be used to measure force, or pressure, as well as motion at the same time. This actuator can assist human and robot motions. At the same time, it can work as a motion feedback sensor. We hope that it may be useful for smart rehabilitation equipment for hands, legs, and fingers. DE has also been shown to operate in reverse as a generator. Experiments have been performed on portable DE generators/wearable generators powered by human motion, ocean wave power harvesters mounted on buoys, solar heat generators, and water turbines. While the power output levels of such demonstration devices is small, the performance of these devices has supported the potential benefits of DE. We are developing elastomers having larger dielectric constant using barium titanium oxide to produce a “super artificial muscle for energy harvesting devices, actuators & sensors” in the near future.

Abstract: Dynamic characteristics of a dielectric elastomer based micro beam resonator are investigated by taking into consideration of squeeze-film damping, large deformation and electrical voltage. The analysis shows that the resonant frequency of the resonator can be tuned through changing applied electrical voltage. It is observed that the natural frequency of the resonator increases with the increase of the vibration amplitude. In addition, the ambient pressure can significantly alter the resonant frequency of the resonator. The analysis is envisaged to provide qualitative predictions and guidelines for design and application of DE-based micro resonators.