Electroactive Nanostructured Polymers as Tunable Actuators

Lightweight and conformable electroactive actuators stimulated by acceptably low electric fields are required for emerging technologies such as microrobotics, flat-panel speakers, micro air vehicles, and responsive prosthetics. High actuation areal strains (> 50 %) are currently afforded by dielectric elas-tomers at relatively high electric fields (> 50 V l m –1 ). In this work, we demonstrate that incorporation of a low-volatility, aliphatic-rich solvent into a nanostructured poly[styrene-b - (ethylene-co -butylene)- b -styrene] triblock copolymer yields physically crosslinked micellar networks that exhibit excellent displacement under an external electric field. Such property development reflects solvent-induced reductions in matrix viscosity and nanostructural order, as well as field-enhanced polarization of the styrenic units, which together result in ultra-high areal actuation strains (>200 %) at significantly reduced electric fields (< 40 V l m –1 ) with remarkably low cyclic hysteresis. Use of nanostructured polymers whose properties can be broadly tailored by varying copolymer characteristics or blend composition represents an innovative and tunable avenue to reduced-field actuation for advanced engineering, biomimetic, and biomedical applications.

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