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[Masafumi Yoshio](https://orcid.org/0000-0002-1442-4352), Che‐Hao Wu, [Chengyang Liu](https://orcid.org/0000-0001-5072-6991)

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[Mechanically Tough Micellar Cubic Liquid‐Crystalline Polymer Electrolytes for Electromechanical Actuators](https://mdr.nims.go.jp/datasets/07c595e6-cebc-4c90-95aa-aa0ebc9186e4)

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Mechanically Tough Micellar Cubic Liquid‐Crystalline Polymer Electrolytes for Electromechanical ActuatorsRESEARCH ARTICLEwww.afm-journal.deMechanically Tough Micellar Cubic Liquid-CrystallinePolymer Electrolytes for Electromechanical ActuatorsMasafumi Yoshio,* Che-Hao Wu, and Chengyang LiuThis study presents a novel micellar cubic ionic liquid-crystalline polymerelectrolyte, featuring an alignment-free spherical structure with unimpeded3D ionic pathways, aimed at enhancing the performance of an ionicelectroactive polymer actuator. The development involved creating amechanically tough and high ion-conductive cubic polymer film through theself-assembly of a wedge-shaped vinyl imidazolium salt and an imidazoliumionic liquid, followed by in situ photopolymerization. The 300 μm-thick-trilayerfilms, consisting of the cubic polymer electrolyte sandwiched betweenpoly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS)electrodes, exhibit remarkable capabilities. These include bearing substantialloads of 4 g with a high blocking force under a DC voltage of 2 V, achieving ahigh bending strain of 0.63% under a low input voltage (±2 V, 0.1 Hz), andboasting a maximum response frequency of 70 Hz. These properties positionthe material for potential applications in soft robots and tactile sensingdevices.1. IntroductionIonic electroactive polymer (iEAP) actuators have garnered sig-nificant attention as practical tools for energy storage and trans-duction. These actuators offer remarkable advantages, includinglow operating voltages, high deformability, controllable gener-ation force, and lightweight properties, making them ideal forthe development of soft electronic devices.[1–3] While many highM. Yoshio, C.-H. Wu, C. LiuResearch Center for Macromolecules & BiomaterialsNational Institute for Materials Science1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, JapanE-mail: YOSHIO.Masafumi@nims.go.jpM. Yoshio, C.-H. Wu, C. LiuGraduate School of Chemical Sciences and EngineeringHokkaido UniversityKita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060–8628, JapanM. YoshioJapan Science and Technology AgencyPRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, JapanThe ORCID identification number(s) for the author(s) of this articlecan be found under https://doi.org/10.1002/adfm.202314087© 2024 The Authors. Advanced Functional Materials published byWiley-VCH GmbH. This is an open access article under the terms of theCreative Commons Attribution License, which permits use, distributionand reproduction in any medium, provided the original work is properlycited.DOI: 10.1002/adfm.202314087-performance iEAP actuators can achievesubstantial bending deformation usingfunctionalized materials rich in ionic liq-uids, they often overlook the aspect of forcegeneration.[4–8] To create iEAP actuatorscapable of both high deformation andforce generation, it is crucial to designthe nanoscale morphologies within theionic polymer electrolytes to effectivelycontrol mechanical characteristics andenhance ion transport. Despite the avail-ability of various nanostructured polymerelectrolytes that perform well in iEAPactuators,[9,10] addressing issues related tothe lack of mechanical properties in physi-cally crosslinked polymer electrolytes andthe undesired plasticization from excessiveionic liquids remains a challenge yet to befully resolved.This paper discusses the potentialof intuitive alignment-free micellar cu-bic structures with spherical symmetry(CubM), comprising hydrophobic spheres encased in hydrophilicshells, as a promising solution for enabling efficient ion migra-tion within a mechanically robust polymer membrane. This ionmigration in the micellar cubic structure occurs by traversing thespherical surface with positive interfacial curvature, which wouldprovide a high-efficiency ion transporting for iEAP actuators.The creation of 3D periodic cubic structures within polymerelectrolytes is of paramount importance.[11–13] These periodic cu-bic structures emerge from the microphase separation of am-phiphilic molecules, dividing space into two interwoven and con-tinuous networks. Within these periodic nanostructures, freeions can diffuse in a 3D open space unimpeded by boundarylayers. Namely, the ion-conductive pathways in a 3D cubic struc-ture exhibit significantly lower tortuosity compared to their coun-terparts in inner conductive columnar and layer structures.[14–17]Additionally, cubic lattices offer higher viscoelastic behavior, con-tributing to enhanced modulus.[11,18] Among the various peri-odic cubic structures, CubM structures are the most commonoccurrence in various lyotropic systems.[19,20] We expect that thepolymer electrolyte, in combination with its viscoelasticity cubicstructure and alignment-free ion pathways, will pave the way forthe development of a new generation of mechanically tough iEAPactuators. However, strategies to construct such normal CubMstructures through self-assembled block copolymers often neces-sitate a careful investigation of their complex thermodynamic be-havior and the selection of suitable functional monomers.[21–24]Adv. Funct. Mater. 2024, 34, 2314087 2314087 (1 of 7) © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbHhttp://www.afm-journal.demailto:YOSHIO.Masafumi@nims.go.jphttps://doi.org/10.1002/adfm.202314087http://creativecommons.org/licenses/by/4.0/http://crossmark.crossref.org/dialog/?doi=10.1002%2Fadfm.202314087&domain=pdf&date_stamp=2024-01-26www.advancedsciencenews.com www.afm-journal.deFigure 1. a) Molecular structure of a taper-shaped ionic LC monomer Vc12 and an ionic liquid [Emim][BF4] (IL). b) Phase-transition temperatures of thebinary mixtures of Vc12 and IL as a function of the mole % of IL. The temperatures were determined through the heating scan in the DSC measurements.G, Colh, CubM, and Iso represent the glassy, hexagonal columnar, micellar cubic, and isotropic liquid phases, respectively. c) The schematic depicts thetransformation of the Colh phase to the CubM phase with the addition of IL, followed by photo-polymerization to produce the polymer film. The iEAPactuator was constructed using the CubM LC membrane sandwiched between PEDOT:PSS electrodes, where the LC electrolyte possesses an alignment-free spherical structure with unimpeded 3D ionic pathways.In response to the immediate challenge in the structural de-sign of the new iEAP actuator, we identified photocured ionicliquid-crystalline (LC) membranes with nanoscale ion channelsas highly favorable candidates. By harnessing the influence ofmolecular shape and interactions on self-assembled ionic liquidcrystals, we could effectively control resulting morphologies andsubsequently polymerize them to obtain free-standing LC mem-branes. We have previously reported several nanostructured LCmembrane-based actuators with hexagonally packed columnar(Colh)[25] and layered (Sm) morphologies,[26] showcasing excep-tional bendability even with low ionic liquid content (<15 wt%).However, these structures necessitate intricate alignment treat-ment of 1D or 2D pathways to achieve optimal performance.Furthermore, we introduced an innovative design concept fora 3D Colh structure, featuring ionophobic cylinder surroundedby ionic shells.[27] This concept establishes a substitution schemeresembling a cubic structure, facilitated by the formation of in-terconnected ionic domains between each LC column. Nonethe-less, the orientation of these LC columns in the membrane hasa relatively minor impact on their mechanical property and ionicconductivity.In this study, we introduce an innovative photocured CubM LCpolymer electrolyte membrane, composed of a polymerizable im-idazolium liquid crystal and an ionic liquid (Figure 1), expertlysandwiched between PEDOT:PSS electrodes. This pioneering de-sign empowers the new generation of iEAP actuators to achievea remarkable ability to bear substantial loads of 4 g with a highblocking force and a high bending strain of 0.63% under a lowinput voltage (±2 V, 0.1 Hz). Remarkably, this exceptional perfor-mance is consistently maintained during stable operation in am-bient conditions for over 10,000 cycles. To the best of our knowl-edge, this study marks the first demonstration of a mechanicallytough thermotropic CubM LC membrane electrolyte successfullyapplied in electromechanical transduction devices.2. Results and DiscussionWe have designed a novel taper-shaped ionic LC monomer (Vc12)to create a well-defined thermotropic CubM LC structure. Vc12consists of two vinyl imidazolium groups and a single alkylchain (Figure 1a). The details of synthetic procedure and its nu-clear magnetic resonance (NMR) spectra were recorded in theSupporting Information (Figures S1 and S2, Supporting Infor-mation). The alkyl chain plays a key role in stabilizing the LCmesophase.[27] The combination of Vc12 and IL results in a broadtemperature range exhibiting Colh and CubM phases with in-terconnected polar domains (Figure 1b). Vc12 exhibits a Colhphase between –23.5 and 152.6 °C upon heating (Figure 2a). Thepolarizing optical microscopy (POM) reveals a fan texture withsome black regions (Figure 2b, upper panel), indicating a com-bined texture resulting from both random and vertically orientedLC columns. Small-angle X-ray scattering (SAXS) pattern dis-plays three distinct peaks at q = 1.29, 2.24, and 2.59 nm–1, cor-responding to the (100), (110), and (200) diffractions of the ColhAdv. Funct. Mater. 2024, 34, 2314087 2314087 (2 of 7) © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH 16163028, 2024, 21, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adfm.202314087 by Cochrane Japan, Wiley Online Library on [27/05/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.afm-journal.dewww.advancedsciencenews.com www.afm-journal.deFigure 2. SAXS profiles for a) Vc12, b) Vc12/IL(40), and c) photopolymerized Vc12/IL(40) at ambient temperature. The insets magnify selected regions.Corresponding POM textures under crossed polarizers (white arrows indicate the directions) are displayed in the upper panels.structure (Figure 2a). The intercolumnar distance is estimated tobe 5.6 nm. As the IL is introduced, there is a gradual decreasein the phase transition temperature from Colh to isotropic liquid(Iso) states. Eventually, when the IL content reaches 40 mol%,the Colh phase undergoes a transformation into the CubM struc-ture. Notably, the POM texture of the CubM phase exhibits nobirefringence (Figure 2b, upper panel), and these CubM samplesdisplay higher viscosity compared to the Colh samples (FigureS3, Supporting Information). The transition from Colh to CubMstructure is primarily induced by the expanded rearrangementof ionophilic moieties within the LC systems. The lattice pa-rameters of CubM structure are determined from SAXS pro-file (Figure 2b). Three obvious scattering at q = 1.03, 1.16, and1.27 nm–1, and tiny peaks at q = 1.65, 1.92, and 2.13 nm–1 are ob-served. The reciprocal spacing ratio of these peaks can be spec-ulated to√4:√5:√6:√10:√14:√16, corresponding to the (200),(210), (211), (310), (321), and (400) diffractions of the CubM phasewith Pm3̄n symmetry.[28]The mixtures of Vc12 and IL (Vc12/IL(x), where x denotes themol% of IL) containing a 0.1 wt% photo-initiator can be polymer-ized upon exposure to UV light (350 nm; 5 mW cm–1). The poly-merization conversion of the vinyl imidazolium group was pri-marily assessed by using FTIR spectroscopy. The characteristicpeak of the vinyl C-H stretching vibration at 3016 or 3014 cm–1 ishardly observed (Figure S4, Supporting Information). However,the isolated C = C stretching vibration peak around 1653 cm–1 isweakened. The free-standing LC films retaining Colh and CubMnanostructures could be easily peeled off from the substrates.SAXS pattern for the photocured Colh LC film of Vc12/IL(30)(PCol/IL(30)) observes the presence of intense d100, d110, and d200peaks (Figure S5a, Supporting Information). This result sup-ported the maintenance of Colh ordering in the membrane withan intracolumnar distance of about 5.7 nm.In addition, the photocured CubM LC film of Vc12/IL(40), de-noted as PCub/IL(40), shows clear diffraction peaks from d200, d210,and d211 planes (Figure 2c). The optically transparent CubM LCfilm exhibits excellent ionic conductivity at room temperature(Figure 3). For example, PCol/IL(30) film shows approximately anorder of magnitude higher ionic conductivity than the PCol/IL(0)film. However, despite the PCub/IL(40) film having only a 10mol% difference in IL content compared to PCol/IL(30) film, itsionic conductivity is greatly enhanced, increasing from 1.6 × 10–6to 4.8 × 10–5 S cm−1. Activation energies were calculated as 74,59, and 35 kJ mol−1 for PCol/IL(0), PCol/IL(30), and PCub/IL(40)electrolyte films, respectively. This significant improvement inionic conductivity was mainly attributed to the ordered micellararrangement and greater IL confinement within the membrane.DSC thermograms show glass transition temperature (Tg) shift-ing from –14 to –31 °C with increasing IL contents (Figure S6,Supporting Information).We demonstrate the bending actuation of a PCub/IL(40)-basedactuator. This actuator was fabricated using the CubM LC mem-brane sandwiched between two sheets of conductive PEDOT:PSSelectrodes. Upon the application of voltage, ions can migratealong the ionophobic spherical surface with minimal energybarrier and then aggregate at the electrode interface to induceFigure 3. Ionic conductivities of PCol/IL(0), PCol/IL(30), and PCub/IL(40)films. The dash lines are fitted by the Arrhenius equation to the data. Theinset photograph shows the PCub/IL(40) film.Adv. Funct. Mater. 2024, 34, 2314087 2314087 (3 of 7) © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH 16163028, 2024, 21, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adfm.202314087 by Cochrane Japan, Wiley Online Library on [27/05/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.afm-journal.dewww.advancedsciencenews.com www.afm-journal.deFigure 4. a) Bending displacement of PCub/IL(40)-based actuator with various frequencies. The inset shows the actuation appearance of PCub/IL(40)-based actuator under 2 V, 0.1 Hz. b) Frequency dependence of the bending strain of the PCol/IL(0), PCol/IL(30), and PCub/IL(40)-based actuators underan AC voltage of 2 V.material bending. This behavior is attributed to the high ionicconductivity and low activation energy of continuous ionic path-ways within the CubM LC structure. The PCub/IL(40)-based actu-ator achieves a maximum displacement of approximately 19 mmat 0.1 Hz under an alternating current (AC) of 2 V (Figure 4a).We have investigated the actuators prepared by photo-crosslinkedLC membranes having 3D interconnected Colh and CubM nanos-tructures, respectively, while the ion was able to shuttle insidethe 3D ionic pathways. The frequency-dependent bending strainis presented in Figure 4b, highlighting the superior performanceof the PCub/IL(40)-based actuator, which exhibits a bending strainof 0.63%, in contrast to the 0.35% observed for the PCol/IL(30)-based actuator under 2 V and 0.1 Hz. To gain insights into thebending actuation mechanism through ion accumulation at theelectrode interface, cyclic voltammetry (CV) measurements wereconducted. Current flow within the PCub/IL(40) and PCol/IL(30)-based actuators exhibits the electric double layer capacitance be-havior at a potential window of –1 V to 1 V (Figure S7a, Support-ing Information). The PCub/IL(40)-based actuator demonstrates aspecific capacitance of approximately 17.9 mF cm–2 at a scan rateof 10 mV s–1, while the PCol/IL(30)-based actuator records 15.1mF cm–2 (Figure S7b, Supporting Information). This minor dif-ference between the two actuators can be attributed to variationsin ion content within the electrolyte layer, despite their distinctnanostructures.As the response frequency increases, the bending strain of theactuators decreases. The PCub/IL(40)-based actuator achieves amaximum response frequency of up to 70 Hz. Our LC actua-tors exhibit exceptional high-frequency oscillation capabilities incomparison to other actuators constructed from block copolymerand amorphous polymer electrolyte materials.[9,29–32] Notably, itis worth highlighting that the PCub/IL(40) membrane containsonly 13.3 wt% ionic liquid, significantly lower than reported high-performance actuators.[26,27]Furthermore, we found the PCol/IL(0)-based actuator withoutIL was still capable of inducing a slight deflection with a strain of0.03% at 2 V and 0.1 Hz. This behavior primarily arises from themotion of anions within the polarization of the LC network. Thebending response induced solely by anions illustrated minimalcurrent generation within the actuator, in stark contrast to thePCol/IL(30) and PCub/IL(40)-based actuators. These results under-score the pivotal role of ionic liquid in the polarized LC network,with even small IL quantities facilitating robust performance,likely attributed to the establishment of 3D ion pathways.In addition, both PCol/IL(30) and PCub/IL(40)-based actua-tors can be effectively operated at a low voltage of AC 0.5 and1 V (Figure S8a, Supporting Information). Furthermore, thePCub/IL(40)-based actuator exhibits exceptional long-term dura-bility, enduring over 10,000 cycles under 2 V and 1 Hz (FigureS8b, Supporting Information). The results support the idea thatthe LC electrolyte membrane with a micellar cubic structure caneffectively and stably transport ions under a voltage supply.We also assessed the generation force of the bending actuatorsfor future application in soft robots. Under an AC voltage of 2 Vat 0.1 Hz, the PCub/IL(40)-based actuator exhibited an impressiveblocking force of 2.7 mN at the tip, estimated to be about 60 timesits own weight. In contrast, the PCol/IL(30)-based actuator yieldedonly 0.96 mN under identical conditions (Figure 5a). The notabledifference in generation force between PCol/IL(30)-based actuatorand PCub/IL(40)-based actuator can be attributed to the momentof inertia resulting from the deformation of the actuators andtheir intrinsic elastic modulus.From the perspective of the inertia moment, the PCub/IL(40)-based actuator possesses a larger moment of inertia than thePCol/IL(30)-based actuator due to its superior bending motion.Consequently, the PCub/IL(40)-based actuator exhibits a higherbending speed, contributing to enhanced kinetic energy. On theother hand, we evaluated their Young’s moduli by tensile test(Figure 5b). The tensile strain-stress curves exhibit a similartrend for both assembled actuators, composed of PCol/IL(30) andPCub/IL(40) electrolytes, along with a pair of PEDOT:PSS elec-trodes, respectively. As a result, Young’s modulus obtained fromthe slope in the initial curve within the 0.5% strain was estimatedto be 409 MPa for PCol/IL(30)-based actuators and 466 MPa forPCub/IL(40)-based actuators. While variations in the thickness ofPEDOT:PSS electrodes might contribute to some differences inmechanical properties, the overall elasticity of the actuator pre-dominantly depends on the electrolyte layer under identical thick-ness conditions. The enhanced elasticity of the PCub/IL(40) elec-trolyte can be attributed to the densely packed micellar sphericalAdv. Funct. Mater. 2024, 34, 2314087 2314087 (4 of 7) © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH 16163028, 2024, 21, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adfm.202314087 by Cochrane Japan, Wiley Online Library on [27/05/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.afm-journal.dewww.advancedsciencenews.com www.afm-journal.deFigure 5. a) Generation force from bending actuators based on PCol/IL(30) and PCub/IL(40) electrolytes, respectively, under an AC voltage of 2 V at0.1 Hz. b) Tensile stress-strain curves of PCol/IL(30) and PCub/IL(40)-based actuators.structure in a unit space. This characteristic is further supportedby the higher storage modulus (G’) observed in the rheologicalmeasurements of the monomeric mixtures (Figure S3, Support-ing Information). In contrast, PCol/IL(30) electrolytes with ran-domly oriented LC columns may have free space between eachLC column, resulting in lower mechanical properties comparedto the PCub/IL(40) electrolyte.The CubM LC electrolyte, with its high viscoelastic frameworkand 3D ion pathway network, has enabled the development of anovel iEAP actuator capable of achieving high deformation andgenerating substantial force. To assess the advantages of thisCubM electrolyte, we compared it with a commercial polyvinyli-dene fluoride (PVdF) electrolyte containing over 30 wt% IL, sand-wiched between PEDOT:PSS electrodes, as a control experiment.The actuator’s dimensions are 20 mm in length, 10 mm in width,and 300 μm in thickness. While the conventional PVdF elec-trolyte actuator shows commendable performance, it cannot sup-port heavy objects (Figure 6a and Movie S1, Supporting Infor-mation). In contrast, the flexible PCub/IL(40)-based actuator ex-hibits remarkable force generation, supporting a 4.0 g aluminumweight (equivalent to four 1 yen coins) in equilibrium under a2 V DC voltage. Notably, the weight of the aluminum coins isover 65 times greater than that of the actuators. While it is possi-ble to achieve impressive generation forces by stacking multiplelayers of electrolytes to fabricate an actuator, this approach oftencomes at the cost of sacrificing the intrinsic benefits of flexibil-ity and high bending displacement. Additionally, it can result inincreased electric resistance between each electrolyte interface.Thanks to the ingenious design principle of a tough cubic LCelectrolyte, we were able to harness the unique advantages of asingle-layer membrane electrolyte, including flexibility, mechan-ical strength, high blocking force, and excellent bending capabil-ities in the actuator.Furthermore, we demonstrated the effectiveness of an elec-tronic pincer constructed from two sheets of PCub/IL(40)-basedactuators. Despite their lightweight nature, these actuators ex-hibited remarkable bending performance, allowing them to se-curely grasp a styrofoam block (Figure 6b). Consequently, ournewly designed cubic LC electrolytes can simultaneously facili-tate efficient physical elastic deformation and ion transport, mak-ing them exceptionally well-suited for soft actuator applications.In our study, iEAP actuators fabricated using the novel CubM LCelectrolyte exhibit remarkable performance even at low ionic liq-uid concentrations, surpassing the bending performance of pre-viously reported actuators (Figure 6c).3. ConclusionIn conclusion, we have presented a novel LC molecular designaimed at creating well-defined micellar cubic LC electrolytes withcontinuous ion pathways. This approach primarily involves thesupramolecular assembly of taper-shaped LC molecules, sur-rounded by IL, into stable spherical structures that remain intactover a wide temperature range. The transition from the originalColh structure to the CubM structure is facilitated by the additionof IL, which not only impacts the structural arrangement but alsoinfluences the mechanical properties. The cubic structure com-bines the advantages of low tortuosity in ion diffusion pathwaysand densely packed ordered molecular spheres, resulting in mul-tifunctional materials. The resultant CubM electrolyte membranepreserves the benefits of being mechanically robust with inter-connected ion pathways, enabling rapid and efficient ion diffu-sion. The tri-layer actuator, composed of the CubM electrolyte anda pair of PEDOT:PSS electrodes, exhibits outstanding actuationperformance under a low driven voltage of 2 V and 0.1 Hz. Thisincludes a high bending strain (0.63%) and a high force genera-tion (2.7 mN) at the tip of actuator, which enables it to lift heavyobjects of 4 g. The design concept based on the construction of aperiodic LC cubic structure represents a significant milestone inthe development of new energy storage and transduction actua-tors.4. Experiment SectionGeneral Preparation Methods: Synthesis of ionic LC monomer (Vc12)and fabrication of PEDOT:PSS films and actuators are described in theSupporting Information.Adv. Funct. Mater. 2024, 34, 2314087 2314087 (5 of 7) © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH 16163028, 2024, 21, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adfm.202314087 by Cochrane Japan, Wiley Online Library on [27/05/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.afm-journal.dewww.advancedsciencenews.com www.afm-journal.deFigure 6. a) The comparison between a control 300 μm thick-actuator made of PVdF polymer electrolyte containing 30 wt% IL and PEDOT:PSS electrodes,which cannot support a 1 yen coin, and our PCub/IL(40)-based actuator of the same thickness, capable of carrying four 1 yen coins, equivalent to 4 g.b) An electronic pincer, constructed from two actuator sheets, securely holds a 150 mg styrofoam block by bending inward. c) The relationship betweenpeak-to-peak bending strain and blocking force for the PCub/IL(40) actuator and other previously reported actuators. The detailed data can be found inTable S2 (Supporting Information).General Analysis Methods: Polarized optical microscopy (POM) obser-vations were performed using an Olympus BX51N-31P-O3 microscopeequipped with a DP22 digital camera and a temperature control sys-tem (LINKAM T95-HS, LTS420E). Differential scanning calorimetry (DSC)measurements were carried out under a continuous argon purge (40 mLmin−1) using a NETZSCH DSC-3500 Sirius instrument connected witha liquid nitrogen cryo-system. The heating and cooling scan rates were10 °C min−1. Small-angle X-ray scattering (SAXS) measurements wereperformed by using Anton Paar SAXSess mc2 instruments. Tensile testswere performed with a Shimadzu EZ-S setup at a stretching speed of10 mm min−1. Rheological measurements were performed using an An-ton Paar MCR 102 rheometer (Anton Paar, Austria). A parallel plate ge-ometry with an 8 mm diameter plate and a gap spacing of 0.3 mmwas used for all the measurements. The measurements were conductedat an angular frequency of 10 rad s−1 and a shear strain amplitude of0.01–1000%.Cyclic Voltammetry Measurements: CV measurements were carried outusing an electrochemical analyzer (model 611E, CH Instruments) in a po-tential range of 1 to −1 V at scan rates varying from 10 to 50 mV s−1.The specific capacitance (Csc) was calculated via the following equation:Csc =∫V2V1i dVA(V2−V1)v, where i is the instant current (A), A is the surface area ofthe electrode (cm2), v is the scan rate (V s−1), V2 and V1 are the high andlow potential limits (V).Ionic Conductivity Measurements: Alternating current impedance mea-surements were carried out using a Metrohm AUTOLAB PGSTAT128Nimpedance analyzer. The frequency range was 102–107 Hz and the ap-plied voltage was 0.6 V. The sample was sandwiched between a pair ofindium tin oxide (ITO)-coated glass substrates using a 55 μm-thick poly-imide tape spacer with a 3 mm-diameter hole. The alignment-dependentionic conductivity was measured in a gap cell geometry using interdigi-tated gold electrodes. The temperature was controlled using a Linkam hotstage. The impedance data were recorded every 10 °C upon heating from25 to 100 °C. They were fitted to the equivalent circuit consisting of a con-stant phase element and a parallel RC element. Ionic conductivity 𝜎 (Scm−1) was calculated as 𝜎 = L/RbA, where Rb is the bulk resistance (Ω),L is the sample thickness (cm), and A is the sample area (cm2). The Rbvalue was obtained from the intercept of a semicircle on the real axis ofimpedance in the Nyquist plots. Temperature-dependent ionic conductivi-ties were fitted by the Arrhenius equation: 𝜎 = 𝜎0 e( −EaRT ), where R = 8.314J K−1 mol−1 is the ideal gas constant, Ea is the activation energy (J mol−1),T is the absolute temperature (K), and 𝜎0 is the pre-exponential factor (Scm−1).Actuation Performance Test: The actuator strip was clamped betweentwo stainless-steel electrodes connected to a potentiostat (Hokuto Denko,HAL3001A). Symmetrical square-wave alternating voltages or direct volt-age generated by a function generator (YOKOGAWA FG400 30 MHz) werecontrolled using the potentiostat and applied to the actuator. The bend-ing displacement was measured using a laser meter (Keyence, LK-H050,and LK-HD500). The laser was irradiated perpendicular to the actuatorsurface at a distance of 7 mm from the electrode. The signals of voltage,current, and displacement were recorded in a digital data logger (HIOKILR8880). The actuation was captured using a USB camera (Sanwa Supply,400-CAM058). The blocking force was measured by the load sensor con-nected to a force detection monitor (KYOWA LTS-50GA/KYOWA WGA-680A). The bending strain (%) was calculated as ɛ = 2𝛿d × 100/(𝛿2 + L2),where 𝛿 is the peak-to-peak displacement, d is the total thickness of theactuator, and L is the free length of the actuator. The actuation tests wereperformed under an ambient atmosphere with an average relative humid-ity of (40 ± 5)%.Supporting InformationSupporting Information is available from the Wiley Online Library or fromthe author.Adv. Funct. Mater. 2024, 34, 2314087 2314087 (6 of 7) © 2024 The Authors. Advanced Functional Materials published by Wiley-VCH GmbH 16163028, 2024, 21, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/adfm.202314087 by Cochrane Japan, Wiley Online Library on [27/05/2024]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons Licensehttp://www.advancedsciencenews.comhttp://www.afm-journal.dewww.advancedsciencenews.com www.afm-journal.deAcknowledgementsThis work was supported by JST, PRESTO (Grant Number JPMJPR23QB),JSPS KAKENHI (Grant Number 21H02021), and Iketani Science and Tech-nology Foundation (no. 0351202-A). The authors thank Dr. Junko Aimi forassistance with the SAXS instrument.Conflict of InterestThe authors declare no conflict of interest.Author ContributionsM.Y. and C.H.W. contributed equally to this work and were designated asthe co-first authors. Conceptualization, methodology, funding acquisition,project administration, and supervision were done by M.Y; Investigation,writing, review, and editing were done by M. Y., C.-H. W., and C. 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Experiment Section Supporting Information Acknowledgements Conflict of Interest Author Contributions Data Availability Statement Keywords