| 1. |
- Abelow, Alexis, et al.
(författare)
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Electroresponsive Nanoporous Membranes by Coating Anodized Alumina with Poly(3,4-ethylenedioxythiophone) and Polypyrrole
- 2014
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Ingår i: Macromolecular materials and engineering. - : Wiley-VCH Verlagsgesellschaft. - 1438-7492 .- 1439-2054. ; 299:2, s. 190-197
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Tidskriftsartikel (refereegranskat)abstract
- Electrically-active nanoporous membranes are prepared by coating the surface of anodized alumina with electroactive polymers using vapor phase polymerization with four combinations of conjugated polymers and doping ions: poly(3,4-ethylenedioxythiophone) and polypyrrole, FeCl3 and FeTs3. The permeability of the polymer-coated membranes is measured as a function of the applied electric potential. A reversible three-fold increase is found in molecular flux of a neutral dye for membranes in oxidized state compared to that in the reduced state. After analyzing various factors that may affect the molecular transport through these membranes, it is concluded that the observed behavior results mostly from swelling/deswelling of the polymers and from the confinement of the polymers inside the nanopores.
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| 2. |
- Admassie, Shimelis, et al.
(författare)
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A renewable biopolymer cathode with multivalent metal ions for enhanced charge storage
- 2014
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Ingår i: JOURNAL OF MATERIALS CHEMISTRY A. - : Royal Society of Chemistry. - 2050-7488. ; 2:6, s. 1974-1979
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Tidskriftsartikel (refereegranskat)abstract
- A ternary composite supercapacitor electrode consisting of phosphomolybdic acid (HMA), a renewable biopolymer, lignin, and polypyrrole was synthesized by a simple one-step simultaneous electrochemical deposition and characterized by electrochemical methods. It was found that the addition of HMA increased the specific capacitance of the polypyrrole-lignin composite from 477 to 682 F g(-1) ( at a discharge current of 1 A g(-1)) and also significantly improved the charge storage capacity from 6(to 128 mA h g(-1).
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| 3. |
- Alici, Gursel, et al.
(författare)
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Conducting Polymers as EAPs: Device Configurations
- 2016
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Ingår i: Electromechanically Active Polymers: A Concise Reference. - Cham : Springer. - 9783319317670 ; , s. 257-292
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter focuses on device configurations based on conjugated polymer transducers. After the actuation and sensing configurations in the literature are presented, some successful device configurations are reviewed, and a detailed account of their operation principles is described. The chapter is concluded with critical research issues. With reference to the significant progress made in the field of EAP transducers in the last two decades, there is an increasing need to change our approach to the establishment of new device configurations, novel device concepts, and cutting-edge applications. To this aim, we should start from the performance specifications and end up with the material synthesis conditions and properties which will meet the performance specifications (top-to-down approach). The question should be “what electroactive material or materials can be used for a specific purpose or application,” rather than looking for an application or a device concept suitable to the unique properties of the EAPs and transducers already made of these materials. The field is mature enough to undertake this paradigm change.
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| 4. |
- Amaia Beatriz, Ortega-Santos, 1995-, et al.
(författare)
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Enzymatic biofuel cells embedded polymer-based soft actuators
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Enzymatic biofuel cells are presented as an untethered alternative energy source that could power small implantable or wearable medical devices. However, most of these catalytic processes do not provide with enough energy to power common small electronic-mechanical devices. On the other hand, conducting polymer-based actuators are of great interest for their biocompatibility, flexibility, processability, possibility to be miniaturized and low power consumption. So far, these artificial muscles have been driven by external power sources that prevent them for being completely autonomous. There is a need for a novel power source to elaborate actuators that could use physiological processes as a driving force. These soft actuators’ low power consumption matches the electrical power generated by the biocatalysis of some enzymes, such as glucose oxidase and laccase in presence of glucose and oxygen in aqueous media. Here, we present the latest results in the development of polypyrrole-based soft actuators powered by enzymatic biofuel cells. The actuator consists of a tri-layer conductive substrate on which the polypyrrole is electrodeposited in both sides. The polypyrrole layers act as the active part, expanding and contracting upon a redox reaction, resulting in a bending movement. Tetrathiofulvlene-7,7,8,8-tetracyanoquinodimethane (TTF-TCNQ) and 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS) electron transfer mediators are cast on the surface of the polypyrrole to help the electron transmission. The glucose oxidase and laccase enzymes are immobilized in the modified-conducting polymer surface, integrating the electrode to the actuator. The bio-catalysis of enzymes in presence of glucose and oxygen in aqueous solution provides the actuator with the electrons needed for the redox reaction, converting the chemical energy into mechanical energy, i.e., movement. The glucose-self-powered soft actuator may contribute to the development of more complex implantable, ingestible, or wearable biomedical devices such as cardio-stimulators, insulin pumps, or muscle implants.
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| 5. |
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| 6. |
- Asadi, Milad, 1987-, et al.
(författare)
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Microfabrication of conjugated polymer actuators on textiles and study of textile structures for scaling up the actuation
- 2019
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Konferensbidrag (refereegranskat)abstract
- Conjugated polymers have been developed over the last decade for applications as artificial muscle. These polymers can be synthesized on the conventional yarns to prepare actuators. When a single yarn is functionalized with such polymers, the isotonic generated strain is very low (around 0.075%). In order to reach the early stages of commercialisation, especially in exo-skeleton devices, it is critical to amplify the actuation mechanism in both isometric force transfer and strain generation. In our previous study we showed that by using a 2´1 rib knitted fabric as a viscoelastic substrate, the generated strain enhances to 3%.However, viscoelastic properties of fabrics are determined not only by the constitutive operators of the fibers but also by the fabric pattern and its structures, which governs the fibre deformation. Here we have studied the actuation mechanism of polypyrrole on various fabric structures.Polyamide 6 and stretchable polyamide 6/PU fibers were used to knit the fabrics. Fabrics were pre-modified with tannic acid and bath sonicated for its stress relaxation. Then, they were dip-coated in PEDOT:PSS solution in order to achieve an electrode layer. Dynamic elastic behaviour of samples was measured before and after applying the seed layer. Further, electrochemical synthesis of polypyrrole on PEDOT:PSS was taken place by a 3-electrode electrochemical cell setup. A dual-mode muscle lever was used to characterize the textile actuators. The results show that the efficiency of actuation mechanism is determined by both viscoelastic properties and stress-relaxation time of textiles.
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| 7. |
- Aziz, Shazed, et al.
(författare)
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Artificial Muscles from Hybrid Carbon Nanotube-Polypyrrole-Coated Twisted and Coiled Yarns
- 2020
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Ingår i: Macromolecular materials and engineering. - : WILEY-V C H VERLAG GMBH. - 1438-7492 .- 1439-2054. ; 305:11
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemically or electrothermally driven twisted/coiled carbon nanotube (CNT) yarn actuators are interesting artificial muscles for wearables as they can sustain high stress. However, due to high fabrication costs, these yarns have limited their application in smart textiles. An alternative approach is to use off-the-shelf yarns and coat them with conductive polymers that deliver high actuation properties. Here, novel hybrid textile yarns are demonstrated that combine CNT and an electroactive polypyrrole coating to provide both high strength and good actuation properties. CNT-coated polyester yarns are twisted and coiled and subjected to electrochemical coating of polypyrrole to obtain the hierarchical soft actuators. When twisted without coiling, the polypyrrole-coated yarns produce fully reversible 25 degrees mm(-1)rotation, 8.3x higher than the non-reversible rotation from twisted CNT-coated yarns in a three-electrode electrochemical system operated between +0.4 and -1.0 V (vs Ag/AgCl). The coiled yarns generate fully reversible 10 degrees mm(-1)rotation and 0.22% contraction strain, 2.75x higher than coiled CNT-coated yarns, when operated within the same potential window. The twisted and coiled yarns exhibit high tensile strength with excellent abrasion resistance in wet and dry shearing conditions that can match the requirements for using them as soft actuators in wearables and textile exoskeletons.
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| 8. |
- Aziz, Shazed, et al.
(författare)
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Fast and High-Strain Electrochemically Driven Yarn Actuators in Twisted and Coiled Configurations
- 2021
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Ingår i: Advanced Functional Materials. - : John Wiley & Sons. - 1616-301X .- 1616-3028. ; 31:10
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Tidskriftsartikel (refereegranskat)abstract
- Commercially available yarns are promising precursor for artificial muscles for smart fabric-based textile wearables. Electrochemically driven conductive polymer (CP) coated yarns have already shown their potential to be used in smart fabrics. Unfortunately, the practical application of these yarns is still hindered due to their slow ion exchange properties and low strain. Here, a method is demonstrated to morph poly-3,4-ethylenedioxythiophene:poly-styrenesulfonate (PEDOT:PSS) coated multifilament textile yarns in highly twisted and coiled structures, providing >1% linear actuation in <1 s at a potential of +0.6 V. A potential window of +0.6 V and -1.2 V triggers the fully reversible actuation of a coiled yarn providing >1.62% strain. Compared to the untwisted, regular yarns, the twisted and coiled yarns produce >9x and >20x higher strain, respectively. The strain and speed are significantly higher than the maximum reported results from other electrochemically operated CP yarns. The yarn’s actuation is explained by reversible oxidation/reduction reactions occurring at CPs. However, the helical opening/closing of the twisted or coiled yarns due to the torsional yarn untwisting/retwisting assists the rapid and large linear actuation. These PEDOT:PSS coated yarn actuators are of great interest to drive smart textile exoskeletons.
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| 9. |
- Aziz, Shazed, 1985-, et al.
(författare)
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PEDOT:PSS coated twisted and coiled yarn actuators
- 2021
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Ingår i: EuroEAP 2021.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Commercial yarns can be functionalized with conducting polymers (CPs) todevelop yarn and textile actuators. Here we show a method of functionalizationof commercial polyamide yarns by poly-3,4-ethylenedioxythiophene:polystyrenesulfonate (PEDOT:PSS) coating. Aftercoating, while PEDOT:PSS is drying, it is possible to twist and coil the yarns,resulting in a major improvement of their linear strain and speed of movement.By using a potential window between +0.6 V and -1.2 V vs Ag/AgCl it waspossible to obtain a fully reversible actuation of a coiled yarn providing up to1.62% strain. A strain higher than 1% was achieved in less than 1 second.Compared to the untwisted, regular yarns, the twisted and coiled yarns produce>9× and >20× higher strain, respectively. These results are a step forward towardsthe development of soft, silent and compliant smart textile exoskeletons.
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| 10. |
- Aziz, Shazed, et al.
(författare)
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Plant-Like Tropisms in Artificial Muscles
- 2023
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095.
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Tidskriftsartikel (refereegranskat)abstract
- Helical plants have the ability of tropisms to respond to natural stimuli, and biomimicry of such helical shapes into artificial muscles has been vastly popular. However, the shape-mimicked actuators only respond to artificially provided stimulus, they are not adaptive to variable natural conditions, thus being unsuitable for real-life applications where on-demand, autonomous operations are required. Novel artificial muscles made of hierarchically patterned helically wound yarns that are self-adaptive to environmental humidity and temperature changes are demonstrated here. Unlike shape-mimicked artificial muscles, a unique microstructural biomimicking approach is adopted, where the muscle yarns can effectively replicate the hydrotropism and thermotropism of helical plants to their microfibril level using plant-like microstructural memories. Large strokes, with rapid movement, are obtained when the individual microfilament of yarn is inlaid with hydrogel and further twisted into a coil-shaped hierarchical structure. The developed artificial muscle provides an average actuation speed of approximate to 5.2% s(-1) at expansion and approximate to 3.1% s(-1) at contraction cycles, being the fastest amongst previously demonstrated actuators of similar type. It is demonstrated that these muscle yarns can autonomously close a window in wet climates. The building block yarns are washable without any material degradation, making them suitable for smart, reusable textile and soft robotic devices.
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