Electroactive Nanostructured Polymers as Tunable Actuators

Abstract

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 elastomers at relatively high electric fields (> 50 V lm -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 ultrahigh areal actuation strains (> 200 %) at significantly reduced electric fields (< 40 V lm -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. Polymeric electroactive materials are capable of mechanical actuation induced by an external electric field and thus afford tremendous promise in emerging technologies ranging from micro air vehicles and flat-panel speakers [1] to active video

Communication: Molecular-level insights into asymmetric triblock copolymers: Network and phase development

“…11 ) Due to their highly elastic molecular network, ABA copolymer systems are ubiquitous in a wide range of contemporary technologies requiring, for example, highly stretchable wires for flexible electronics, 12 nanostructured membranes for fuel cells, 13 micromolded substrates for microfluidics, 14 high permittivity nanocomposites for sensors, 15 and energy-efficient dielectric elastomers for actuators and energy-harvesting media. [16][17][18] Here, we seek to follow the transition from diblock copolymers, a soft materials archetype responsible for elucidating the mechanism of molecular self assembly, to triblock copolymers, another soft materials archetype in which a) Authors to whom correspondence should be addressed. Electronic addresses: mbanasz@amu.edu.pl and rich_spontak@ncsu.edu.…”

Capture and Release Erythrocyte from the Blood with Thermoresponsive and Core‐Sheath PCL/PNIPAAm Nanofibers

“…The formation of core-sheath structure is mainly attributed to the self-assembly of PCL/PNIPAAm blends during electrospinning. [ 12,23 ] Because PNIPAAm and PCL dissolve much differently in DMF, phase separation is thermodynamically favored. Meanwhile, the system attempts to attain a state of minimum energy dissipation during the fl ow in the needle, the lower viscosity fl uid (PNIPAAm) is kinetically located at the walls.…”

Infrared-Triggered Actuators from Graphene-Based Nanocomposites

“…9,10 Although many electrical-triggered actuator materials, such as dielectric elastomers and conducting polymers, 8,11,12 are well-known and are used in a wide range of frontier technologies, they are still handicapped in some practical applications by high voltages, electric wires fixed in the devices, and so on. 3 Correspondingly, an optical-induced actuator, compared to the actuators driven by other stimuli, offers an alternative means to couple energy remotely into actuator structures, which brings larruping advantages such as wireless actuation, remote control, and high-level integrity.…”

“…1,2 Current actuator materials, which can be classified into electrical, thermal, pneumatic, and optical actuators depending on their corresponding energy supplies, 3,4 have been widely adopted in a variety of technological uses, including temperature-sensitive switches, 2 microrobotics, 5 artificial muscle, 1,[6][7][8] and even molecular machines. 9,10 Although many electrical-triggered actuator materials, such as dielectric elastomers and conducting polymers, 8,11,12 are well-known and are used in a wide range of frontier technologies, they are still handicapped in some practical applications by high voltages, electric wires fixed in the devices, and so on.…”