This book shows the fundamentals, theories, and applications of dielectric elastomers (DEs). This book consists of ten chapters. This book firstly introduces the definition and fundamental principle of DEs and presents typical DE materials. Then, typical DEs and their nanocomposites are described in detail. Subsequently, the fundamental of dielectric elastomer theory is also reviewed, which includes the constitutive theory, failure models, stability, transition theory, and so on. Moreover, the mechanical behavior of nonlinear dielectric elastomers, the electromechanical phase transition, electromechanical instability, dynamic mechanical behavior, and electric field induced changes are also presented. Finally, due to the great potential in intelligent bionics, aerospace, mechanical engineering, the applications of DEs are reviewed in this book, which includes the actuators with different structures, sensors, energy harvesters, robots, artificial muscles, minimum energy structures, Braille tactual displays, vibrators, loudspeaker, micropump, tunable lens, etc. This book is interesting and useful to a wide readership in the various fields of mechanics and materials science.

Jinsong Leng is a professor at Harbin Institute of Technology, China. He is a Member of Chinese Academy of Sciences, the Foreign Member of Academia Europaean. He received his B.S. and Ph.D. in engineering mechanics and composite materials from HIT in 1990 and 1996, respectively. He is the director of the Center for Smart Materials and Structures (http://smart.hit.edu.cn/). His research interests cover shape memory polymers and composites, 4D printing, sensors and actuators, structural health monitoring, and multifunctional nanocomposites.

Yanju Liu is a Distinguished Professor of the Changjiang Scholars Program in the Department of Astronautical Science and Mechanics at Harbin Institute of Technology, China. She obtained her Ph.D. degree in material science from HIT, China in 1999. Her research interests are in the field of smart materials and structures, including stimuli-responsive materials, such as electroactive polymers, shape memory polymers, and their composites.

Liwu Liu is a Distinguished Professor of the Changjiang Scholars Program in the Department of Astronautical Science and Mechanics at Harbin Institute of Technology, China. He received his Ph.D. degree in solid mechanics from HIT in 2012. His research interests include electroactive polymers, soft robotics, shape memory polymers, and their composites.