Characterization of Conjugated Polymer Actuation under Cerebral Physiological Conditions

Daneshvar, Eugene D.; Smela, Elisabeth

doi:10.1002/adhm.201300610

Cited by 19 publications

(10 citation statements)

References 66 publications

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“…As can be seen in Figure S3 (Supporting Information), the actuator showed the normal reversible movement as previously seen for such trilayer actuators, indicating that the actuator was functioning correctly. The movement was reduced in the physiological PBS electrolyte as compared to simple NaDBS salt solution, which is consistent with previous results using cerebral physiological solutions . Operating at a slightly lower pH should not influence its performance …”

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confidence: 91%

Artificial Muscles Powered by Glucose

et al. 2019

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Untethered actuation is important for robotic devices to achieve autonomous motion, which is typically enabled by using batteries. Using enzymes to provide the required electrical charge is particularly interesting as it will enable direct harvesting of fuel components from a surrounding fluid. Here, a soft artificial muscle is presented, which uses the biofuel glucose in the presence of oxygen. Glucose oxidase and laccase enzymes integrated in the actuator catalytically convert glucose and oxygen into electrical power that in turn is converted into movement by the electroactive polymer polypyrrole causing the actuator to bend. The integrated bioelectrode pair shows a maximum open‐circuit voltage of 0.70 ± 0.04 V at room temperature and a maximum power density of 0.27 µW cm−2 at 0.50 V, sufficient to drive an external polypyrrole‐based trilayer artificial muscle. Next, the enzymes are fully integrated into the artificial muscle, resulting in an autonomously powered actuator that can bend reversibly in both directions driven by glucose and O2 only. This autonomously powered artificial muscle can be of great interest for soft (micro‐)robotics and implantable or ingestible medical devices manoeuvring throughout the body, for devices in regenerative medicine, wearables, and environmental monitoring devices operating autonomously in aqueous environments.

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confidence: 91%

Artificial Muscles Powered by Glucose

et al. 2019

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“…It is well known that the electrically conductive polymer polypyrrole (PPy) reversibly exchanges ions with a surrounding electrolyte under control of the electrode potential, E , and that this process changes the volume of the polymer [ 1–8 ] in proportion to the transferred charge density, δq V (charge per volume PPy). [ 2–4,9–12 ] Good environmental [ 13 ] and electrochemical cycling stabilities, [ 14 ] a low operating voltage [ 15 ] and strain amplitudes up to 40% [ 14,16–18 ] are exploited for actuation with PPy.…”

Section: Introductionmentioning

confidence: 99%

Nanoporous‐Gold‐Polypyrrole Hybrid Materials for Millimeter‐Sized Free Standing Actuators

Roschning

Weißmüller

2020

Adv Materials Inter

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An important materials parameter of actuators is their strain-charge coupling coefficient, ψ = δε/δq V , where ε denotes the linear, uniaxial strain. For PPy, the magnitude and sign of ψ depend on the synthesis conditions, the species of transferred ions, the solvent and the mechanical boundary conditions. [4,5,11,21-23] Besides the magnitude of the straincharge coupling, the response time is an important characteristic of actuators. For PPy, the underlying charge transport kinetics include both, ionic transport and the formation of electronically conducting zones along the polymer chains. [24,25] If the potential interval is restricted so that the PPy is kept in its oxidized state with high electronic conductivity, the ion exchange is rate controlling. Similar to classical interdiffusion, the time constant for equilibration after a change in E increases with the square of the diffusion distance. [24-26] Acceptable response times thus require small actuator dimensions in at least one direction. Therefore, many studies investigate PPy as a thin film (typically not exceeding 10 µm) on an electrically conductive substrate. Examples for such actuators are bilayered bending cantilevers [27-29] which may exhibit roughened interfaces for enhanced adhesion, [30] multilayered axial strain actuators [31] or coated fibers spun to yarns. [10] Nanometer-thin PPy films allow for particularly fast reaction times. [15,32] For PPy films with a thickness of about 10 µm, the actuation response time increases to minutes. [33,34] Free-standing PPy actuators with a thickness of ≈100 µm and a cross-sectional gradient in microstructure have been investigated in the context of wireless actuation. [35,36] They exhibit similar response times. For even thicker geometries, the response will be prohibitively slow. PPy actuators with spatial dimensions of mm or above can be realized with PPy-coated nanoskeleton structures, such as multi-walled carbon nanotube networks [37] or electrospun microribbons. [38] In these architectures, a liquid electrolyte in the pore space provides a fast pathway for long-range ion transport. Metal-PPy-electrolyte hybrid materials obtained by the imbibition of PPy-coated nanoporous metals [39] represent a particularly interesting case, because their skeleton structure is load-bearing under compression. This enables actuation against an external compressive load by free-standing macroscopic bodies without a supporting device structure. Furthermore, the mechanical behavior of nanoporous metals has been intensively studied. [40-45] This provides the opportunity for a This work studies the actuation of hybrid materials made from nanoporous gold, polypyrrole, and aqueous electrolyte. The deposition protocol affords a conformal polypyrrole coating on the entire internal interface of millimetersized nanoporous metal specimens made by dealloying. The hybrid material emerges when the remaining pore space is filled with perchloric acid. The metal serves as load-bearing and electronically conductive substrate, the polypyrrole...

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“…They can not only be actuated in biological electrolytes, but actively use the surrounding media as the ion source resulting in a simpler device geometry. This allows their use in medical devices and in applications in cell biology, organic bioelectronics, active catheters for the vascular system and cochlear electrode array [99][100][101][102]. A microrobotic arm and manipulator, microfluidics, smart pill, microvalve [31], tactile transducer [103] were demonstrated with CPs [104][105][106][107].…”

Section: Conducting Polymersmentioning

confidence: 99%

Review of Soft Actuator Materials

Kim

Zhai

et al. 2019

Int. J. Precis. Eng. Manuf.

151

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Soft actuator materials change their shape or size in response to stimuli like electricity, heat, light, chemical or pH. These actuator materials are compliant and well suited for soft mechatronics and robots. This paper introduces the definition of soft materials and the position of soft actuator materials in comparison with conventional actuators and other solid state actuator materials. A thorough review of selected soft actuator materials is carried out, including responsive gels/hydrogels, ionic polymer metal composites, conducting polymers, carbon nanotubues/graphenes, dielectric elastomers, shape memory polymers and biopolymers. This review will give insights for applications of soft actuator materials via better understanding of the materials in terms of their preparation, performance and limitation.

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Characterization of Conjugated Polymer Actuation under Cerebral Physiological Conditions

Cited by 19 publications

References 66 publications

Artificial Muscles Powered by Glucose

Artificial Muscles Powered by Glucose

Nanoporous‐Gold‐Polypyrrole Hybrid Materials for Millimeter‐Sized Free Standing Actuators

Review of Soft Actuator Materials

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