**6. Acknowledgment**

412 Thermoplastic Elastomers

Fig. 10. Comparison between Maxwell stress contribution, RM and true electrostriction contribution, RES, of SEBS and MA thermoplastic dielectric elastomer to the strain sensitivity, *R*33 at 15 V/m. R33 represents the sum of RM and RES (Kim et al., 2011).

In this book, we demonstrated that thermoplastic dielectric elastomers are distinguished from conventional homopolymer dielectric elastomers such as acrylics and silicones in many aspects such as nanostructure morphology, shape memory property and electric actuation mechanism. Unlike conventional homopolymer dielectric elastomers with one phase structure, these thermoplastic dielectric elastomers exhibit a well defined microphaseseparated nanostructure owing to the molecular architecture. That kind of nanostructure results in the physical-crosslink-induced shape memory effect which is quite different from chemical-crosslink-induced shape memory effect of conventional dielectric elastomers. Most of all, thermoplastic dielectric elastomers have much larger true electrostrictive coefficients than conventional homopolymer dielectric elastomers, thus show the much fabulous electric actuation properties even at low electric field. Such unique behavior basically stems from the presence of a high density of dielectric mismatched nanostructures. As a result, we consider thermoplastic dielectric elastomers as fascinating actuation materials, although many challenges still remains for the real applications. We hope that, in future, this thermoplastic dielectric elastomer approach contributes to opening an era of polymer

**5. Conclusion** 

transducers.

This work was financially supported by a grant from the Fundamental R&D Program for Core Technology of Materials funded by the Ministry of Knowledge Economy, Republic of Korea, and partially by a grant from the Nano Hybrids Center of Korea Institute of Science and Technology (KIST).
