Prestrain‐Free Dielectric Elastomers Based on Acrylic Thermoplastic Elastomer Gels: A Morphological and (Electro)Mechanical Property Study

Abstract

Recent efforts have established that thermoplastic elastomer gels (TPEGs) composed of styrenic triblock copolymers swollen with a midblock-selective solvent exhibit remarkable electromechanical properties as high-performance dielectric elastomers. This class of electroactive polymers typically requires high electric fi elds for actuation, and a shortcoming that continues to thwart the widespread commercialization of such materials in general is the need to apply mechanical prestrain prior to electroactuation to decrease fi lm thickness and, thus, the electric potential required to promote actuation. To alleviate this requirement, TPEGs consisting of acrylic triblock copolymers differing in molecular weight and composition, and swollen with a high dielectric, midblock-selective solvent are investigated. Synchrotron small-angle x-ray scattering is used to probe the nanoscale morphologies of the resultant materials, and analysis of quasi-static and cyclic tensile properties provides additional insight into both blend morphologies and electroactuation effi cacy. Actuation strains measured in the absence of mechanical prestrain exceed 100% on an area basis, and electric fi elds capable of inducing actuation are as low as ∼ 20 kV/mm. Failure occurs by either electromechanical instability or dielectric breakdown, depending on the copolymer and TPEG composition employed. The electromechanical properties of these acrylic-based TPEGs match or exceed those of skeletal muscle, in which case they constitute an attractive and unexplored alternative to existing dielectric elastomers.

Morphological Investigation of Midblock‐Sulfonated Block Ionomers Prepared from Solvents Differing in Polarity

“…Physical incorporation of a midblock-selective, low-volatility organic solvent into a nonpolar TPE tends to swell the molecular network, thereby yielding a thermoplastic elastomer gel (TPEG) at low copolymer concentrations (but above the critical gel concentration). [20][21][22][23] These soft materials possess highly tunable (electro)mechanical properties and are of considerable interest in the development of dielectric elastomers, [24][25][26][27] fl exible electronics [ 28 ] and microfl uidic substrates. [ 29 ] In some instances, ABA-triblock copolymers have been specifi cally designed with a nonionic hydrophilic (typically ethoxylated [30][31][32] ) middle block to facilitate inclusion of water, ionic liquids, or other polar liquids for use in contemporary technologies such as personal-care products, fuel cells, and separation membranes.…”

Thermoplastic Dielectric Elastomer of Triblock Copolymer with High Electromechanical Performance

“…Interestingly, the triblock elastomers are easily processed. Some commercially available ABA triblock copolymer elastomers have been explored as dielectric elastomers . It was found that the single component of the triblock copolymer showed poor electromechanical performance .…”

Characterization of Viscoelasticity and Self‐Healing Ability of VHB 4910

“…Recently, we discovered that a commercially available elastomer, VHB 4910, demonstrates a good compromise of the mechanical strength and the self‐healing ability. Due to its good mechanical strength and electro‐active properties, this material shows a potential to be used as a dielectric actuator . In addition, it's application in artificial muscles has been suggested .…”