| Conventional means of converting electrical energy to mechanical work are generally considered too noisy and bulky for many contemporary technologies such as microrobotic, microfluidic, and haptic devices. Dielectric electroactive polymers (D-EAPs) constitude a growing class of electroactive polymers (EAP) that are capable of producing mechanica work induced by an applied electric field. D-EAPs are considered remarkably efficient and well suited for a wide range of applications, including ocean-wave energy harvesters and prosthetic devices. However, the real-world application of D-EAPs is very limited due to a number of factors, one of which is the difficulty of producing high actuation strains at acceptably low electric fields.;D-EAPs are elastomeric polymers and produce large strain response induced by external electric field. The electromechanical properties of D-EAPs depend on the dielectric properties and mechanical properties of the D-EAP. In terms of dielectric behavior, these actuators require a high dielectric constant, low dielectric loss, and high dielectric strength to produce an improved actuation response. In addition to their dielectric properties, the mechanical properties of D-EAPs, such as elastic moduli and hysteresis, are also of importance. Therefore, material properties are a key feature of D-EAP technology.;DE actuator materials reported in the literature cover many types of elastomers and their composites formed with dielectric fillers. Along with polymeric matrix materials, various ceramic, metal, and organic fillers have been employed in enhancing dielectric behavior of DEs.;This work describes an effort to characterize elastomer blends and composites of different matrix and dielectric polymer fillers according to their dielectric, mechanical, and electromechanical responses. This dissertation focuses on the development and characterization of polymer-polymer blends and composites from a high-k polyurethane (PU) and polydimethylsiloxane (PDMS) elastomers. Two different routes were followed with respect to elastomer processing: The first is a simple solution blending of the two types of elastomers, and the second is based on preparation of composites from PU nanofiber webs and PDMS elastomer. Both the blends and the nanofiber web composites showed improved dielectric and actuation characteristics. |
