Synthetic Dielectric Elastomer Materials

Chapter 6 is focused on dielectric elastomer materials. In particular, a synthetic elastomer is proposed to enhance the actuation performance and energy density. Methods for preparing the materials are discussed, and various material properties as relevant to the actuation performance are characterized and compared with commercially available dielectric materials. In addition, by incorporating suitable additives, the synthetic elastomer has shown favorable behavior for actuation purposes. 

Thirdly, synthetic elastomer was proposed in the effort of finding a new dielectric elastomer material. Comprehensive performance characterization proved that the new material has the highest energy density among the tested materials and the actuation is feasible. Furthermore, by adding different fillers, the properties of the synthetic elastomer material can be adjusted as needed. For instance, different content of DOP and Ti02 show better radial strain of actuation and also increase the elastic energy of the material. 

We can see that when the content of the DOP is increased, the electric field required to actuate the dielectric elastomer is reduced, while the output radial strain is nearly the same, as is shown in Fig. 6.18(a). This occurs because the DOP causes the elastic modulus of the material to decrease, although at the same time there is a decrease in permittivity of the material. In addition, Fig. 6.18(b) illustrates that the contents of the Ti02 at 40 PHR creates a synthetic elastomer with better actuation than the other contents in the same electric field. However, the electric field strength of the material in this case is lower than in the case where the content of the Ti02 is... 

One view of materials development is to search for what materials correspond to empty spaces on a hypothetical multi-dimensional map of the properties of available materials. Following a biomimetic philosophy, for instance, it can be seen that tough ceramics and moldable short fiber eomposites with high moduli are possible but absent from the list of available synthetic materials. Likewise artificial muscle is missing, where the properties are defined as a developed stress of over 300 kPa, a hnear contraction of 25 % and a response time of below one second. Currently dielectric elastomers come closest but have disadvantages [1, 2]. 

In this section, experimental studies on the major properties of the synthetic elastomer have been conducted in comparison with several commercial ones. Dielectric constant, elastic modulus, and stress relaxation of elastomeric materials commercially available such as VHB4905/4910 and KE441 silicone are compared with the proposed one. 

In the effort of finding a new DE, the synthetic elastomer is proposed. Its improved performance characterized with dielectric constant, elastic modulus and stress relaxation can be proved with the highest energy density among the materials tested. Under the comprehensive comparisons with the materials commercially available, its possibility as means of actuation is validated. Additionally, the synthetic elastomer properties can be adjusted based on the different contents of the fillers added to the synthetic elastomer. Different additives can be added to this material to create new DE which can be adapted to our requirements. Future research activity may focus on the development of a new composite synthetic elastomer-filler that can accommodate more requirements of our applications. 

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