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Zhang, Chenghong, Bin He, Zhipeng Wang, Yanmin Zhou et Aiguo Ming. « Application and Analysis of an Ionic Liquid Gel in a Soft Robot ». Advances in Materials Science and Engineering 2019 (2 mai 2019) : 1–14. http://dx.doi.org/10.1155/2019/2857282.
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Due to their light weight, flexibility, and low energy consumption, ionic electroactive polymers have become a hotspot for bionic soft robotics and are ideal materials for the preparation of soft actuators. Because the traditional ionic electroactive polymers, such as ionic polymer-metal composites (IPMCs), contain water ions, a soft actuator does not work properly upon the evaporation of water ions. An ionic liquid polymer gel is a new type of ionic electroactive polymer that does not contain water ions, and ionic liquids are more thermally and electrochemically stable than water. These liquids, with a low melting point and a high ionic conductivity, can be used in ionic electroactive polymer soft actuators. An ionic liquid gel (ILG), a new type of soft actuator material, was obtained by mixing 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), hydroxyethyl methacrylate (HEMA), diethoxyacetophenone (DEAP) and ZrO2 and then polymerizing this mixture into a gel state under ultraviolet (UV) light irradiation. An ILG soft actuator was designed, the material preparation principle was expounded, and the design method of the soft robot mechanism was discussed. Based on nonlinear finite element theory, the deformation mechanism of the ILG actuator was deeply analyzed and the deformation of the soft robot when grabbing an object was also analyzed. A soft robot was designed with the soft actuator as the basic module. The experimental results show that the ILG soft robot has good driving performance, and the soft robot can grab a 105 mg object at an input voltage of 3.5 V.
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Hermenegildo, B., R. M. Meira, A. G. Díez, D. M. Correia, S. Ribeiro, J. P. Serra, C. Ribeiro, L. Pérez-Álvarez, José L. Vilas-Vilela et S. Lanceros-Méndez. « Ionic liquid modified electroactive polymer-based microenvironments for tissue engineering ». Polymer 246 (avril 2022) : 124731. http://dx.doi.org/10.1016/j.polymer.2022.124731.
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Hillman, A. Robert, Karl S. Ryder, Hani K. Ismail, Asuman Unal et Annelies Voorhaar. « Fundamental aspects of electrochemically controlled wetting of nanoscale composite materials ». Faraday Discussions 199 (2017) : 75–99. http://dx.doi.org/10.1039/c7fd00060j.
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Electroactive films based on conducting polymers have numerous potential applications, but practical devices frequently require a combination of properties not met by a single component. This has prompted an extension to composite materials, notably those in which particulates are immobilised within a polymer film. Irrespective of the polymer and the intended application, film wetting is important: by various means, it facilitates transport processes – of electronic charge, charge-balancing counter ions (“dopant”) and analyte/reactant molecules – and motion of polymer segments. While film solvent content and transfer have been widely studied for pristine polymer films exposed to molecular solvents, extension to non-conventional solvents (such as ionic liquids) or to composite films has been given much less attention. Here we consider such cases based on polyaniline films. We explore two factors, the nature of the electrolyte (solvent and film-permeating ions) and the effect of introducing particulate species into the film. In the first instance, we compare film behaviours when exposed to a conventional protic solvent (water) with an aprotic ionic liquid (Ethaline) and the intermediate case of a protic ionic liquid (Oxaline). Secondly, we explore the effect of inclusion of physically diverse particulates: multi-walled carbon nanotubes, graphite or molybdenum dioxide. We use electrochemistry to control and monitor the film redox state and change therein, and acoustic wave measurements to diagnose rheologicallyvs.gravimetrically determined response. The outcomes provide insights of relevance to future practical applications, including charge/discharge rates and cycle life for energy storage devices, “salt” transfer in water purification technologies, and the extent of film “memory” of previous environments when sequentially exposed to different media.
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Khmelnitskiy, I. K., V. M. Aivazyan, N. I. Alekseyev, A. P. Broyko, V. V. Luchinin et D. O. Testov. « Investigation of Ionic EAP Actuators with Metal and Polymer Electrodes in Aqueous Medium ». Nano- i Mikrosistemnaya Tehnika 23, no 1 (24 février 2021) : 32–43. http://dx.doi.org/10.17587/nmst.23.32-43.
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Electroactive polymers (EAP) are promising materials for creating electromechanical transducers. Among ionic EAP, ionic polymer-metal composites (IPMC), which are an ion-exchange membrane with metal electrodes on both sides, have been widely spread and well studied. The evolutionary development of IPMC results in ionic polymer-polymer composites (IP2C), in which polymer electrodes are used. To obtain IPMC actuators with platinum electrodes, the method of chemical reduction from the salt solution was chosen, and to obtain IP2C actuators with PEDOT electrodes, the method of in situ polymerization of the monomer on the membrane surface was chosen. Samples of 2x0.5 cm in size based on the MF-4SK membrane with a thickness of 290 μm were preliminarily kept in deionized water (H+ form) and in 0.1 M CuSO4 aqueous solution (Cu2+ form), after which their performance was studied in air, in deionized water, as well as in aqueous solutions of CuSO4 and NaCl. When applying a DC voltage and a sine wave AC voltage, a decrease in the maximum displacement and peak-to-peak displacement of the IPMC actuators and IP2C actuators with an increase in the ionic strength of the liquid was observed, except for the case of the IPMC actuator operation in CuSO4 aqueous solutions. In all considered media, the IPMC actuators and IP2C actuators in Cu2+ form displaced more strongly than the corresponding samples in H+ form, except for the IP2C actuators in deionized water. The largest peak-to-peak displacement was demonstrated by the IPMC actuators in Cu2+form when operating in air (5 mm) and the IP2С actuators in H+ form when operating in deionized water (8.4 mm).
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Kulesza, Pawel J., Iwona A. Rutkowska, Claudia Janiszewska, Vito Di Noto, Keti Vezzu et Enrico Negro. « (Invited) Development and Characterization of Polyoxometallate-Based Systems for Aqueous Redox Flow Batteries ». ECS Meeting Abstracts MA2022-01, no 48 (7 juillet 2022) : 1999. http://dx.doi.org/10.1149/ma2022-01481999mtgabs.
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Redox flow batteries are of potential importance to both large scale energy storage and powering the electrical vehicle. It is now accepted that flow batteries are the battery technology with the greatest potential to be one of the key elements in the energy transition to a sustainable electricity supply. Among critical challenges are low volumetric energy density of redox electrolytes, high cost and the maintenance limitations that greatly impede the wide application of conventional flow batteries. In this respect, the redox-active charge-storage material has a significant impact on the performance of a flow battery. The concentration of redox centers and their reaction kinetics have an influence on the available current densities and, thus, the power of the device. Many inorganic and organic electroactive systems have been proposed as alternatives to vanadium species in redox flow batteries. In the study, we explore the concept that highly concentrated solutions of the polyoxometallates of molybdenum and tungsten can serve as model examples of multi-electron systems for all-liquid redox flow batteries and related fundamental investigations. Polyoxometallates are polynuclear inorganic materials with well-defined multi-electron reversible electrochemistry and electrocatalytic properties [1]. Among other important characteristics of heteropolyacids are that they exhibit very strong Brønsted acidity, act as proton conductors, and undergo fast, reversible, multi-electron electron transfers leading to the formation of highly conducting, mixed-valence (e.g. tungsten(VI,V) or molybdenum(VI,V) heteropoly blue) compounds. The polyoxometallate-based redox electrolytes have different chemical identities, and they could be considered as anolytes or catholytes, depending on their redox potentials but, typically, their use would require formation of an asymmetric system with different-type redox species. The scope of existing inorganic and organic electroactive materials can be expanded due the possibility of their functionalization and structural modification. Recent developments in the area of the transition-metal-derivatized polyoxometallates are also promising [2] because they imply the feasibility of formation of the bi-redox polyoxmetallate-based electrolytes. In particular, the systems containing such metals as copper, iron, ruthenium, nickel or tin could of interest. Such features as the feasibility of reversible multi-electron redox processes, the improved potential output and cycling performance, sufficiently high solubility and reasonable stability will be examined here. An alternative approach can be based on the preparation of robust zeolite-type cesium salts of polyoxometallates, Cs2.5H0.5PMo12O40, Cs2.5H1.5SiMo12O40, Cs2.5H0.5PW12O40, and Cs2.5H1.5SiW12O40. It is noteworthy that, at certain contents of cesium (or rubidium), these porous salts are characterized by fast charge propagation. They can be considered for application in a form of colloidal suspensions. While kinetics of electrochemical processes has an influence on the systems’ current densities, the viscosity of the electrolyte and the mass transport dynamics are also affected by the choice of the redox-active material and its concentration. Trying to develop useful electroanalytical diagnostic criteria, we are going to extend the historical concepts of charge propagation in semi-solid or semi-liquid systems developed for mixed-valence redox polymers and polynuclear materials to the development of redox electrolytes. Fundamental electroanalytical approaches utilizing ultramicrodisk electrodes and interdigitated arrays will be adapted to characterization of solid suspensions synthesized in a form of stable colloidal solutions utilizing redox active centers capable of exhibiting fast electron transfers according to electron hopping mechanism. Of additional interest is the dynamics of electron transfer at the electrolyte/electrode interface, considered at the molecular and monolayer scales. [1] I.A. Rutkowska, P.J. Kulesza, “Metal Oxide Cluster and Polyoxometallate Supports for Noble Metal Nanoparticles in Efficient Electrocatalysis” in Encyclopedia of Interfacial Chemistry: Surface Science and Electrochemistry, Elsevier, vol. 5, pp 207–216, 2018. [2] J. Goura, B.S. Bassil, J.K. Bindra, I.A. Rutkowska, P.J. Kulesza, N.S. Dalal, U. Kortz, Chemistry - A European Journal 26 (2020) 15821 – 15824.
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Dong, Yuqing, Ka-Wai Yeung, Chak-Yin Tang, Wing-Cheung Law, Gary Chi-Pong Tsui et Xiaolin Xie. « Development of ionic liquid-based electroactive polymer composites using nanotechnology ». Nanotechnology Reviews 10, no 1 (1 janvier 2021) : 99–116. http://dx.doi.org/10.1515/ntrev-2021-0009.
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Abstract This review is intended to provide an overview of the design and fabrication of ionic liquid-based ionic electroactive polymer (IL-iEAP) transducers for advanced applications in biological and electronic fields. The iEAP is a class of smart materials that can perform sensing or actuating functions by controlling the movement of cations and anions in the active layer. This type of material can deform under low voltage stimulation and generate electrical signals when undergoing mechanical deformation because of ion redistribution. Numerous research attention has been focused on studying the deformation mechanisms and the potential for actuation, sensing, and energy harvesting applications. Compared to the traditional water-based iEAP, the non-volatile IL-iEAP delivers a wider electrochemical window and a more stable actuation performance. In this paper, the classification of iEAP with different actuation mechanisms is first outlined, followed by introducing various preparation methods including nanotechnology for IL-iEAPs, and discussing the key factors governing their actuation performance. In addition, the advanced functions of IL-iEAP in actuating and sensing, especially self-sensing in bionics and electromechanical equipment applications, are reviewed. Finally, novel nanotechnologies used for fabricating IL-iEAPs and the prospects of their microelectromechanical system (MEMS) applications are discussed.
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Meira, R. M., D. M. Correia, S. Ribeiro, P. Costa, A. C. Gomes, F. M. Gama, S. Lanceros-Méndez et C. Ribeiro. « Ionic-Liquid-Based Electroactive Polymer Composites for Muscle Tissue Engineering ». ACS Applied Polymer Materials 1, no 10 (30 août 2019) : 2649–58. http://dx.doi.org/10.1021/acsapm.9b00566.
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Miguel, Álvaro, Francisco González, Víctor Gregorio, Nuria García et Pilar Tiemblo. « Solvent-Free Procedure for the Preparation under Controlled Atmosphere Conditions of Phase-Segregated Thermoplastic Polymer Electrolytes ». Polymers 11, no 3 (1 mars 2019) : 406. http://dx.doi.org/10.3390/polym11030406.
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A solvent-free method that allows thermoplastic solid electrolytes based on poly(ethylene oxide) PEO to be obtained under controlled atmosphere conditions is presented. This method comprises two steps, the first one being the melt compounding of PEO with a filler, able to physically crosslink the polymer and its pelletizing, and the second the pellets’ swelling with an electroactive liquid phase. This method is an adaptation of the step described in previous publications of the preparation of thermoplastic electrolytes by a single melt compounding. In comparison to the single step extrusion methodology, this new method permits employing electroactive species that are very sensitive to atmospheric conditions. The two-step method can also be designed to produce controlled phase-segregated morphologies in the electrolyte, namely polymer-poor and polymer-rich phases, with the aim of increasing ionic conductivity over that of homogeneous electrolytes. An evaluation of the characteristics of the electrolytes prepared by single and two-step procedures is done by comparing membranes prepared by both methods using PEO as a polymeric scaffold and a solution of the room-temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMI TFSI) and the bis(trifluoromethanesulfonyl) imide lithium salt (Li TFSI) as liquid phase. The electrolytes prepared by both methods have been characterized by Fourier transform infrared spectroscopy and optic microscopy profilometry, differential scanning calorimetry, self-creep experiments, and dielectric spectroscopy. In this way, the phase separation, rheology, and ionic conductivity are studied and compared. It is striking how the electrolytes prepared with this new method maintain their solid-like behavior even at 90 °C. Compared to the single step method, the two-step method produces electrolytes with a phase-separated morphology, which results in higher ionic conductivity.
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Fernandes, Liliana C., Rafaela M. Meira, Daniela M. Correia, Clarisse Ribeiro, Eduardo Fernandez, Carmen R. Tubio et Senentxu Lanceros-Méndez. « Electrospun Magnetic Ionic Liquid Based Electroactive Materials for Tissue Engineering Applications ». Nanomaterials 12, no 17 (4 septembre 2022) : 3072. http://dx.doi.org/10.3390/nano12173072.
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Functional electrospun fibers incorporating ionic liquids (ILs) present a novel approach in the development of active microenviroments due to their ability to respond to external magnetic fields without the addition of magnetic particles. In this context, this work reports on the development of magnetically responsive magneto-ionic fibers based on the electroactive polymer poly(vinylidene fluoride) and the magnetic IL (MIL), bis(1-butyl-3-methylimidazolium) tetrathiocyanatocobaltate ([Bmim]2[(SCN)4Co]). The PVDF/MIL electrospun fibers were prepared incorporating 5, 10 and 15 wt.% of the MIL, showing that the inclusion of the MIL increases the polar β-phase content of the polymer from 79% to 94% and decreases the crystallinity of the fibers from 47% to 36%. Furthermore, the thermal stability of the fibers decreases with the incorporation of the MIL. The magnetization of the PVDF/MIL composite fibers is proportional to the MIL content and decreases with temperature. Finally, cytotoxicity assays show a decrease in cell viability with increasing the MIL content.
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Wang, Fang, Chong Xie, Liying Qian, Beihai He et Junrong Li. « Study on the Preparation of Ionic Liquid Doped Chitosan/Cellulose-Based Electroactive Composites ». International Journal of Molecular Sciences 20, no 24 (9 décembre 2019) : 6198. http://dx.doi.org/10.3390/ijms20246198.
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Electro-actuated polymer (EAP) can change its shape or volume under the action of an external electric field and shows similar behavioral characteristics with those of biological muscles, and so it has good application prospects in aerospace, bionic robots, and other fields. The properties of cellulose-based electroactive materials are similar to ionic EAP materials, although they have higher Young’s modulus and lower energy consumption. However, cellulose-based electroactive materials have a more obvious deficiency—their actuation performance is often more significantly affected by ambient humidity due to the hygroscopicity caused by the strong hydrophilic structure of cellulose itself. Compared with cellulose, chitosan has good film-forming and water retention properties, and its compatibility with cellulose is very excellent. In this study, a chitosan/cellulose composite film doped with ionic liquid, 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac), was prepared by co-dissolution and regeneration process using [EMIM]Ac as the solvent. After that, a conductive polymer, poly(3,4-ethylenedioxythiophene)/poly (styrene sulfonate) (PEDOT: PSS), was deposited on the surface of the resulted composite, and then a kind of cellulose-based electroactive composites were obtained. The results showed that the end bending deformation amplitude of the resulted material was increased by 2.3 times higher than that of the pure cellulose film under the same conditions, and the maximum deformation amplitude reached 7.3 mm. The tensile strength of the chitosan/cellulose composite film was 53.68% higher than that of the cellulose film, and the Young’s modulus was increased by 72.52%. Furthermore, in comparison with the pure cellulose film, the water retention of the composite film increased and the water absorption rate decreased obviously, which meant that the resistance of the material to changes in environmental humidity was greatly improved.
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Wang, Fan, Seong Young Ko, Jong Oh Park, Suk Ho Park et Chang Doo Kee. « Electroactive Polymer Actuator Based on PVDF and Graphene through Electrospinning ». Advanced Materials Research 1105 (mai 2015) : 311–14. http://dx.doi.org/10.4028/www.scientific.net/amr.1105.311.
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We report a novel high-performance electroactive polymer actuator based on poly (vinylidene fluoride) (i.e., PVDF) and graphene. The PVDF-graphene composite membranes were fabricated through electrospinning method. The electrospun composite membrane has a three-dimensional network structure, high porosity, and large ionic liquid solution uptake which are a prerequisite for high performance dry-type electroactive soft actuators. The conductive poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT:PSS) layers were deposited on the surfaces of the composite membrane through dipping-drying method. The electroactive PVDF-graphene actuators under both harmonic and step electrical inputs show larger bending deformation and faster response time than the pure PVDF actuator. X-ray diffusion (XRD) and ionic conductivity testing results for the PVDF-graphene membrane were compared with those of pristine PVDF. Most important, the PVDF-graphene actuator shows much larger bending deformation under low input voltage, and this could be due to the synergistic effects of the higher ionic conductivity of PVDF-graphene membrane and the electrochemical doping processes of the PEDOT:PSS electrode layers.
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Elhi, Fred, Karl Karu, Pille Rinne, Kadi-Anne Nadel, Martin Järvekülg, Alvo Aabloo, Tarmo Tamm, Vladislav Ivaništšev et Kaija Põhako-Esko. « Understanding the Behavior of Fully Non-Toxic Polypyrrole-Gelatin and Polypyrrole-PVdF Soft Actuators with Choline Ionic Liquids ». Actuators 9, no 2 (21 mai 2020) : 40. http://dx.doi.org/10.3390/act9020040.
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Smart and soft electroactive polymer actuators as building blocks for soft robotics have many beneficial properties that could make them useful in future biomimetic and biomedical applications. Gelatin—a material exploited for medical applications—can be used to make a fully biologically benign soft electroactive polymer actuator that provides high performance and has been shown to be harmless. In our study, these polypyrrole-gelatin trilayer actuators with choline acetate and choline isobutyrate showed the highest strain difference and highest efficiency in strain difference to charge density ratios compared to a reference system containing imidazolium-based ionic liquid and a traditional polyvinylidene fluoride (PVdF) membrane material. As neither the relative ion sizes nor the measured parameters of the ionic liquids could explain their behavior in the actuators, molecular dynamics simulations and density functional theory calculations were conducted. Strong cation-cation clustering was found and the radial distribution functions provided further insight into the topic, showing that the cation-cation correlation peak height is a good predictor of strain difference of the actuators.
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Kulesza, Pawel J., Iwona A. Rutkowska, Claudia Janiszewska, Keti Vezzu, Enrico Negro et Vito Di Noto. « Ultramicroelectrode Based Approaches to Diagnose Utility of Redox Electrolytes in Flow Batteries ». ECS Meeting Abstracts MA2022-02, no 30 (9 octobre 2022) : 1100. http://dx.doi.org/10.1149/ma2022-02301100mtgabs.
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Redox flow batteries are of potential importance to both large scale energy storage and powering the electrical vehicle. Among critical challenges are low volumetric energy density of redox electrolytes, high cost and the maintenance limitations that greatly impede the wide application of conventional flow batteries. In this respect, the redox-active charge-storage material has a significant impact on the performance of a flow battery. The concentration of redox centers and their reaction kinetics have an influence on the available current densities and, thus, the power of the device. Many inorganic and organic electroactive systems have been proposed as alternatives to vanadium species in redox flow batteries. In the study, we explore the concept of highly concentrated solutions of such redox systems as iodine/iodide and poloxometallates of molybdenum and tungsten, and the possibility of optimizing their performance to exhibit high rates of charge propagation. While the iodine/iodide system can be prepared at high concentrations, the polyoxometallates of molybdenum and tungsten can serve as model examples of multi-electron systems for all-liquid redox flow batteries and related fundamental investigations. Reactions in the zinc/iodine (polyiodide) redox flow battery are as follows: Zn → Zn2+ + 2e- (E = −0.76 V vs SHE) at the negative electrode (anode), and 3I- → I3 − + 2e− (E = 0.54 V vs SHE) at the positive electrode (cathode) thus yielding a total theoretical potential output as high as ∼1.3 V. The increase of current density could be achieved not only by reducing the viscosity of the electrolyte, thus accelerating charge-carrier transport, but also – by referencing to our experience with the iodine/iodide couple as charge relay for dye-sensitized solar cells – through improvement of the dynamics of charge propagation in highly concentrated iodine/iodide solution via the catalyzed enhancement of rates of electron self-exchange (hopping) between iodine/iodide (polyiodide) redox species as well as by accelerating the interfacial kinetics at electrodes. This can be realized by choosing appropriate electrode materials and through their activation or modification. The electrochemical activities of the redox couples are usually significantly increased through application of nanostructured functionalized carbons. While dispersed in solutions they can improve electron transfers to the redox sites. The proposed chemistry has been first tested using the microelectrode methodology to determine mass-transport (effectively diffusional) coefficients for charge propagation, heterogeneous and homogeneous (electron self-exchange) rates of electron transfers. Unless catalyzed, both interfacial and bulk (self-exchange) electron transfers involving the iodine/iodide redox system are somewhat complicated; there is a need to break the I-I bond in the I3 -or I2 molecule; it has also been well-established that platinum (e.g. when deposited on the counter electrode) induces electron transfers within the iodine/iodide redox system. As far as heteropolyacids are concerned, they exhibit very strong Brønsted acidity, act as proton conductors, and undergo fast, reversible, multi-electron electron transfers leading to the formation of highly conducting, mixed-valence (e.g. tungsten(VI,V) or molybdenum(VI,V) heteropoly blue) compounds. The polyoxometallate-based redox electrolytes have different chemical identities, and they could be considered as anolytes or catholytes, depending on their redox potentials but, typically, their use would require formation of an asymmetric system with different-type redox species. While dynamics of electrochemical processes has an influence on the systems’ current densities, the viscosity of the electrolyte and the mass transport dynamics are also affected by the choice of the redox-active material and its concentration. Trying to develop useful electroanalytical diagnostic criteria, we are going to extend the historical concepts of charge propagation in semi-solid or semi-liquid systems developed for mixed-valence redox polymers and polynuclear materials to the development of redox electrolytes. Fundamental electroanalytical approaches utilizing ultramicrodisk electrodes and interdigitated arrays will be adapted to characterization of redox electrolytes.
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Fernandes, Liliana C., Daniela M. Correia, Eduardo Fernández, Mohammad Tariq, José M. S. S. Esperança et Senentxu Lanceros-Méndez. « Design of Ionic-Liquid-Based Hybrid Polymer Materials with a Magnetoactive and Electroactive Multifunctional Response ». ACS Applied Materials & ; Interfaces 12, no 37 (18 août 2020) : 42089–98. http://dx.doi.org/10.1021/acsami.0c10746.
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Maksimkin, Aleksey V., Tarek Dayyoub, Dmitry V. Telyshev et Alexander Yu Gerasimenko. « Electroactive Polymer-Based Composites for Artificial Muscle-like Actuators : A Review ». Nanomaterials 12, no 13 (1 juillet 2022) : 2272. http://dx.doi.org/10.3390/nano12132272.
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Unlike traditional actuators, such as piezoelectric ceramic or metallic actuators, polymer actuators are currently attracting more interest in biomedicine due to their unique properties, such as light weight, easy processing, biodegradability, fast response, large active strains, and good mechanical properties. They can be actuated under external stimuli, such as chemical (pH changes), electric, humidity, light, temperature, and magnetic field. Electroactive polymers (EAPs), called ‘artificial muscles’, can be activated by an electric stimulus, and fixed into a temporary shape. Restoring their permanent shape after the release of an electrical field, electroactive polymer is considered the most attractive actuator type because of its high suitability for prosthetics and soft robotics applications. However, robust control, modeling non-linear behavior, and scalable fabrication are considered the most critical challenges for applying the soft robotic systems in real conditions. Researchers from around the world investigate the scientific and engineering foundations of polymer actuators, especially the principles of their work, for the purpose of a better control of their capability and durability. The activation method of actuators and the realization of required mechanical properties are the main restrictions on using actuators in real applications. The latest highlights, operating principles, perspectives, and challenges of electroactive materials (EAPs) such as dielectric EAPs, ferroelectric polymers, electrostrictive graft elastomers, liquid crystal elastomers, ionic gels, and ionic polymer–metal composites are reviewed in this article.
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Park, Minjeong, Sangwoo Kim, Keun Yong Sohn, Seonpil Kim et Minhyon Jeon. « Poly(3,4-ethylene dioxythiophene):Poly(styrene sulfonate)-Functionalized Reduced Graphene Oxide Electrode for Ionic Electroactive Polymer Actuators ». Science of Advanced Materials 12, no 3 (1 mars 2020) : 313–18. http://dx.doi.org/10.1166/sam.2020.3642.
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Ionic electroactive polymer (IEAP) actuators, which offer advantages such as reduced device weight, flexibility, and large deformation under low voltages (1–5 V), have found utility in applications such as biomimetic robots, actuators, and sensors. In this context, in this study, we fabricate poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)-reduced graphene oxide (PEDOT:PSS-rGO) composite paper electrodes for actuator application. PEDOT:PSS-rGO paper electrodes are prepared by vacuum filtration of a PEDOT:PSS-rGO mixture that is subsequently subjected to heat treatment under an argon atmosphere via furnace annealing. We find that a 5:1 weight ratio of PEDOT:PSS-GO provides the lowest sheet resistance. We next fabricate a PEDOT:PSS-rGO actuator via filtration and the hot-pressing method with rGO paper electrodes, which have hydrophobic properties and low liquid permeability that effectively prevents water evaporation, and we examine its actuating performance. Our results indicate that after functionalization with PEDOT:PSS, the electrical properties and surface roughness of PEDOT:PSS-rGO composite paper electrode are improved. Further, the mechanical properties of the IEAP actuator based on the PEDOT:PSS-rGO paper electrodes exhibits enhanced performance by a factor of 4 relative to an actuator with conventional rGO electrodes.
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Kesküla, Arko, Ivo Heinmaa, Tarmo Tamm, Nihan Aydemir, Jadranka Travas-Sejdic, Anna-Liisa Peikolainen et Rudolf Kiefer. « Improving the Electrochemical Performance and Stability of Polypyrrole by Polymerizing Ionic Liquids ». Polymers 12, no 1 (6 janvier 2020) : 136. http://dx.doi.org/10.3390/polym12010136.
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Polypyrrole (PPy) based electroactive materials are important building blocks for the development of flexible electronics, bio-sensors and actuator devices. As the properties and behavior of PPy depends strongly on the operating environment—electrolyte, solvent, etc., it is desirable to plant immobile ionic species into PPy films to ensure stable response. A premade ionic polymer is not optimal in many cases, as it enforces its own structure on the conducting polymer, therefore, polymerization during fabrication is preferred. Pyrrole (Py) was electropolymerized at low temperature together with a polymerizable ionic liquid (PIL) monomer in a one-step polymerization, to form a stable film on the working electrode. The structure and morphology of the PPyPIL films were investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FTIR) spectroscopy and solid-state NMR (ssNMR) spectroscopy. The spectroscopy results confirmed the successful polymerization of Py to PPy and PIL monomer to PIL. The presence of (TFSI–) anions that balance the charge in PPyPIL was confirmed by EDX analysis. The electrical properties of PPyPIL in lithium bis(trifluoromethanesulfonyl)-imide (LiTFSI) aqueous and propylene carbonate solutions were examined with cyclic voltammetry (CV), chronoamperometry, and chronopotentiometry. The blend of PPyPIL had mixed electronic/ionic conductive properties that were strongly influenced by the solvent. In aqueous electrolyte, the electrical conductivity was 30 times lower and the diffusion coefficient 1.5 times higher than in the organic electrolyte. Importantly, the capacity, current density, and charge density were found to stay consistent, independent of the choice of solvent.
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Stenger-Smith, John D., William W. Lai, David J. Irvin, Gregory R. Yandek et Jennifer A. Irvin. « Electroactive polymer-based electrochemical capacitors using poly(benzimidazo-benzophenanthroline) and its pyridine derivative poly(4-aza-benzimidazo-benzophenanthroline) as cathode materials with ionic liquid electrolyte ». Journal of Power Sources 220 (décembre 2012) : 236–42. http://dx.doi.org/10.1016/j.jpowsour.2012.07.068.
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Zhao, Yusen, Mutian Hua, Yichen Yan, Shuwang Wu, Yousif Alsaid et Ximin He. « Stimuli-Responsive Polymers for Soft Robotics ». Annual Review of Control, Robotics, and Autonomous Systems 5, no 1 (17 novembre 2021). http://dx.doi.org/10.1146/annurev-control-042920-014327.
Texte intégralRésumé :
This article reviews recent progress in the use of stimuli-responsive polymers for soft robotics. First, we introduce different types of representative stimuli-responsive polymers, which include liquid crystal polymers and elastomers, hydrogels, shape memory polymers, magnetic elastomers, electroactive polymers, and thermal expansion actuators. We focus on the mechanisms of actuation and the evaluation of performance and discuss strategies for improvements. We then present examples of soft robotic applications based on stimuli-responsive polymers for bending, grasping, walking, swimming, flying, and sensing control. Finally, we discuss current opportunities and challenges of stimuli-responsive soft robots for future study. Expected final online publication date for the Annual Review of Control, Robotics, and Autonomous Systems, Volume 5 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Neubauer, Justin, Kwang J. KIM et Kwang Jin Kim. « Tunable polyvinyl chloride (PVC) and thermoplastic polyurethane (TPU)-based soft polymer gel sensors ». Smart Materials and Structures, 14 octobre 2022. http://dx.doi.org/10.1088/1361-665x/ac9a8f.
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Abstract Polyvinyl chloride (PVC) gels have recently been found to exhibit mechanoelectrical transduction under mechanical deformation. These mechanoelectrical properties of PVC gels are largely uncharacterized and the underlying transduction mechanisms are currently unknown. These soft electroactive polymers have tunable properties such as modulus and response voltage based on physical dimensions and the amount of plasticizer content within the material making them ideal candidates for complaint sensors. This study aims to investigate PVC gels comprised of various plasticizers to further investigate underlying mechanisms of mechanoelectrical transduction and broaden possible sensing applications. Plasticizers used in this study include dibutyl adipate DBA, dibutyl phthalate (DBP), dioctyl phthalate, otherwise known as bis(2-ethylhexyl) phthalate (DOP or DEHP), diisodecyl adipate (DIDA), and the environmentally friendly biodegradable plasticizer acetyl tributyl citrate (ATBC). ATBC is often used in cosmetics and food packaging applications and is even used as a food additive which may lead to future biocompatibility for these gel sensors. These plasticizers are used to produce PVC gel sensors that are experimentally tested for mechanoelectrical transduction properties and sensing performance. In this study, a Langmuir adsorptive model is fit to the collected mechanoelectrical transduction data. These results are also nondimensionalized and compared to the characteristic dimensionless Langmuir adsorptive model. This simple model agrees very well with the experimental data. Additionally, a study on the mechanoelectrical transduction of an alternative polymer lattice structure, thermoplastic polyurethane (TPU), is discussed. This is a novel electroactive polymer investigated for mechanoelectrical transduction properties. This portion of the study aims to further knowledge of underlying mechanisms of mechanoelectrical transduction as well as show feasibility of additional lattices for soft polymer gel sensors. These TPU gel sensors show strikingly similar mechanoelectrical transduction properties to analogous PVC gels, insinuating that the polymer structure has a limited role in the underlying sensing mechanism and PVC itself is not unique to polymer gel sensing. The TPU based soft polymer gel sensors however do display some level of mechanoelectrical hysteresis which may be attributed to viscoelastic properties and display a small amount of fatigue possibly due to exudation of liquid plasticizer. This study provides further characterization of mechanoelectrical response for varying plasticizers, provides a theoretical framework for underlying mechanisms, and displays the potential for further polymeric gel sensors.
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Lin, Jun-Hong. « The Investigation of the Charge Transport Properties of Ionic Liquids in Response to Step Voltages in Ionic Polymer Actuators ». MRS Proceedings 1660 (2014). http://dx.doi.org/10.1557/opl.2014.784.
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ABSTRACTDeveloping advanced ionic electroactive devices such as ionic actuators and supercapacitors requires the understanding of charge drifting and diffusion processes, which depends on the distances over which the ions travel. The charge dynamics of Aquivion membrane actuators with EMI-Tf ionic liquid are investigated over a broad film thickness (d) range. A time domain charge dynamic method based on Poisson-Nernst-Planck relation is employed to evaluate the charge transport behaviors in the actuators. It is found that for the initial charging process the double layer time τDL is linearly proportional to the film thickness (d). However, for the later charging process under a high applied voltage (>0.5V ) where the substantial electromechanical reaction occurs, the charge transport behavior does not follow the d2 dependence as predicted by the random walk diffusion model. For comparison the charge dynamics of BMI-PF6 ionic liquid films without polymer was also investigated.
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Cao, Siyu, Junko Aimi et Masafumi Yoshio. « Electroactive Soft Actuators Based on Columnar Ionic Liquid Crystal/Polymer Composite Membrane Electrolytes Forming 3D Continuous Ionic Channels ». ACS Applied Materials & ; Interfaces, 31 août 2022. http://dx.doi.org/10.1021/acsami.2c11029.
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Hatipoglu, Gokhan, Yang Liu, Ran Zhao, Mitra Yoonessi, Dean M. Tigelaar, Srinivas Tadigadapa et Q. M. Zhang. « A High-Modulus Electroactive Polymer Acting as a Robust Ionomer for Ionic Micro-Actuators ». MRS Proceedings 1403 (2012). http://dx.doi.org/10.1557/opl.2012.372.
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ABSTRACTA high modulus, sulfonated polymer synthesized from one-to-one ratio 4,6-bis(4-hydroxyphenyl)-N, N-diphenyl-1,3,5-triazin-2-amine and 4,4′-biphenol with bis(4-fluorophenyl) sulfone (DPA-PS:BP) is exploited as an ionomer for micro-ionic actuators. A unique and attractive feature of the ionomer is that it can contain high amounts of ionic liquid (IL) as an electrolyte while maintaining a high elastic modulus (i.e 600 MPa for 150 wt% uptake), which is more than one order of magnitude higher than the state-of-the-art of ionomers with working electrolytes. Such a high modulus makes it possible for the ionomer to be fabricated into micro-actuators with high uptake of ILs and low operation voltage (< 4 V), in various free standing forms with ion milling techniques, which are attractive for MEMS applications. As an initial demonstration of a DPA-PS:BP based ionic micro-actuator, a cantilever (200 μm x 33 μm x 5 μm) is manufactured by Focused Ion Beam (FIB) and characterized. Under the voltage of 1.6 V, the bending actuator exhibits an intrinsic strain from the active ionomer of 1.1% and a corresponding blocking force of 27 μN.
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Washington, Alexandrea, Zakai Olsen, Ji Su et Kwang Jin Kim. « A physics-based modeling of a hydraulically amplified electrostatic actuator ». Journal of Physics Communications, 21 juillet 2022. http://dx.doi.org/10.1088/2399-6528/ac8335.
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Abstract The focus of this study is to understand the physical phenomenon of the liquid-based electroactive polymer (EAP) actuator known as the Hydraulically Amplified Self-Healing Electrostatic (HASEL) actuator. Specifically, this study provides data in several areas, including the deformation of the film material, the dynamics of the dielectric liquid, and the electrical conditions within the actuator body. A two-dimensional model was developed in the finite element software, COMSOL Multiphysics, to create a generalized physics-based framework that describes the actuation mechanism. Much of the predictive data agreed well with the experimental data, such as the electrode pull-in occurring at ~4.5 kV and the displacement-voltage behavior. More importantly, the model also predicts basic fluid dynamic data, such as velocity (which reached a maximum of 0.7 m/s), the pressure of the fluid within the enclosed film, and the motion of the fluid, which have not been found in previous models. The model also predicts phenomenon seen in experimentation, such as fluid pockets under the electrodes and the interesting displacement-voltage behavior. Everything considered, the model connects the electrical, mechanical, and fluid systems, thus providing more detail about the dynamics of the actuator system and facilitating a shift in the current approach to modeling and designing these actuators.
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Dwivedi, Arpit, et Rodney Roseman. « In-situDevelopment and Study of Conducting Polymer Electrodes on PVDF Substrates for Electro-Acoustic Application in Cochlear Implants ». MRS Proceedings 771 (2003). http://dx.doi.org/10.1557/proc-771-l4.46.
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AbstractSensorineural hearing loss (profound deafness) is a result of the inability of the transductory structures in the cochlea (organ of Corti) to convert the mechanical displacement of the basilar membrane to neural signals. A class of devices known as Cochlear Implants can significantly enhance the hearing ability in these patients. Fundamentally different from the existing cochlear implant technology, are the totally implantable piezoelectric based devices that are being developed. The unit is completely self-contained, designed to work without any signal amplifiers or transmission elements, greatly simplifying the stimulation process, and enhancing the cosmetic appearance of the patient. These devices utilize the bending piezoelectric effect. Device design consists of arrays of elements of piezoelectric polymer films with conducting polymer electrodes embedded in a flexible substrate with the whole device coated with an insulating layer. The incoming mechanical energy (pressure waves) into the cochlea generates electrical charge by virtue of the piezoelectric effect of the film. The generated charge is fed to electrical connections evaporated on the substrate and is used to stimulate surviving nerve fibers in the cochlea. In certain environments where acoustic impedance matching is limited by size constraints and conducting liquid medium, the advantage of polymer based devices over ceramics and metal based devices, are their flexibility, low acoustic impedance, and high sensitivity. However, in order to utilize these useful properties, the electrode material is an important issue, since the conventionally used metal electrodes, have high acoustic impedance and also impose mechanical clamping on the soft polymer which can significantly reduce the electromechanical efficiency of the transducer. Due to its flexibility, strong coherent interfaces, and significantly improved acoustic transparency, such an all-polymer electroactive system is compared to a metal-polymer system of similar design and also compared to the current technology.