Nafion Actuator Research Articles

Enhanced electromechanical performance of Nafion actuator doped by poly(ethylene glycol)‐grafted graphene oxide

AbstractCurrent ionic polymer–metal composite (IPMC) actuators have severe actuation drawbacks (i.e. low force output and poor stability), hampering their applications. To address these issues, poly(ethylene glycol)‐grafted graphene oxide (PEG‐GO) is synthesized and incorporated into a Nafion matrix, thus producing a PEG‐GO hybrid Nafion film with better physiochemical properties for fabricating a high‐performance, low‐cost IPMC actuator. The modification of PEG to GO not only prevents GO agglomeration and sedimentation, but also avoids loss of PEG in water. Driven by a 0.2 Hz, 2.5 V electric field, the hybrid IPMC actuator exhibits superior electromechanical behaviors, i.e. a swing angle of 110.3°, a blocking force of 6.89 mN and a stable working time of 485 s, respectively increasing by 92%, 209% and 294% when compared to a pure Nafion actuator. © 2024 Society of Chemical Industry.

Polymer actuators of fluorene derivatives with enhanced inner channels and mechanical performance

A novel ion-exchange polymer-metal composite (IPMC) actuator is fabricated by sandwiching sulfonated fluorene blocked polysulfone (SDPF-b-PSU) between two Pt nanograin sheets. With increased concentration of chlorosulfonic acid, the SDPF-b-PSU film with more sulfonic groups exhibits strong ion exchange capacity, high Li+ ion conductivity, and ordered phase separation, which may contain an increased number of cations and possess larger and better interconnected inner channels for ion migration, thus providing the power to produce large force and power outputs. The SDPF-b-PSU film also exhibits enhanced mechanical performance and water uptake when compared to the pure Nafion film, providing a strong, hydrated matrix to support IPMC functions. At the driving voltage of 4V, the SDPF-b-PSU actuator exhibits a strong force output which is 11 folds higher than that of the pure Nafion actuator.

Nanomaterial-based ionic polymer metal composite insect scale flapping wing actuators

ABSTRACTSmall size actuators (8 mm × 1 mm), IPMNC (RuO2/Nafion) and IPMNC (LbL/CNC) are studied for flapping at the frequency of insects and compared to Platinum IPMC-Pt. Flapping wing actuators based on IPMNC (RuO2/Nafion) are modeled with the size of three dragonfly species. To achieve maximum actuation performance with Sympetrum Frequens scale actuator with optimized Young's modulus, the effect of variation of thickness of electrode and Nafion region of Sympetrum Frequens scale actuator is studied. A trade-off in the electrode thickness and Young's modulus for dragonfly size IPMNC-RuO2/Nafion actuator is essential to achieve the desirable flapping performance.

Study on the Mechanical Characteristics of Ionic Polymer Actuators

Sulfonated endcapped poly (arylenethioethersulfone) copolymer (SPTES) was synthesized through direct copolymerization of sulfonated monomers and poly (vinyl alcohol) (PVA) was crosslinked with SPTES by the dehydration method. The mechanical characteristics of polymer actuators are investigated. Nafion actuators as a comparison were also investigated. The normalized tip displacements were calculated for both PVA/SPTES actuators and Nafion actuators in order to delete the dimensions influence on the bending behaviours. The bending performances were tested under AC excitations with different frequencies. The results showed that the normalized tip displacement decreased with both the width and length of the IPMC strips. That is due to the increase of the monment inetia of the IPMC strips with the increment of the width or the length increment will lead to the larger resistance force from ambient water along with the increase of the area of IPMC strips. PVA/SPTES actuators showed comparable bending performances compared with its Nafion counterparts based on the study of mechanical properties.

Bending deformation characteristics of actuator with anion exchange polymer membrane and polyaniline electrode

To remove the metal electrode and comprise all-organic ionic polymer actuators, tri-layer actuators with anion exchange membranes and conducting polymer electrode were purposely fabricated by the simple attaching method with or without an adhesive layer. Three grades of Neosepta were used as the anion exchange membrane, and polyaniline (PANi) as the electrode. Despite the oxidation/reduction occurring, PANi functioned as the electrode for the actuators. The bending displacement of 7 mm was measured, which was comparable to that of the typical Nafion actuator. As the initial bending direction was the same as an actuator with a cation exchange membrane, the bending characteristics of the actuators and structural change in PANi during actuation were investigated. Open image in new window

Improved performance of carbon nanotube buckypaper and ionic-liquid-in-Nafion actuators for rapid response and high durability in the open air

Abstract The fabrication and electromechanical performance of three layer actuators (carbon nanotube/Nafion/carbon nanotube) with doped Nafion were studied. The Nafion actuators were doped with 1-butyl-3methylimmidazolium tetrafluoroborate (BMI+BF4−) ionic liquid, which was verified by electrochemical impedance spectroscopy analysis. The three layer actuators were fabricated using a simple method involving a doping and hot-pressing process. Carbon nanotube thin films (buckypaper or BP) were used as the electrode layers for fabricating the actuators. The actuators doped with the ionic liquid generated electromechanical strains up to 0.4%, which was ten times higher than when testing the neat Nafion three layer actuators. The results were promising for manufacturing lightweight, low power smart structures.

Thickness dependence of curvature, strain, and response time in ionic electroactive polymer actuators fabricated via layer-by-layer assembly

Ionic electroactive polymer (IEAP) actuators containing porous conductive network composites (CNCs) and ionic liquids can result in high strain and fast response times. Incorporation of spherical gold nanoparticles in the CNC enhances conductivity and porosity, while maintaining relatively small thickness. This leads to improved mechanical strain and bending curvature of the actuators. We have employed the layer-by-layer self-assembly technique to fabricate a CNC with enhanced curvature (0.43 mm−1) and large net intrinsic strain (6.1%). The results demonstrate that curvature and net strain of IEAP actuators due to motion of the anions increase linearly with the thickness of the CNC as a result of the increased volume in which the anions can be stored. In addition, after subtracting the curvature of a bare Nafion actuator without a CNC, it is found that the net intrinsic strain of the CNC layer is independent of thickness for the range of 20–80 nm, indicating that the entire CNC volume contributes equivalently to the actuator motion. Furthermore, the response time of the actuator due to anion motion is independent of CNC thickness, suggesting that traversal through the Nafion membrane is the limiting factor in the anion motion.

Enhanced actuation in functionalized carbon nanotube–Nafion composites

The fabrication and electromechanical performance of functionalized carbon nanotube (FCNT)–Nafion composite actuators were studied. The CNTs were modified successfully with polyethylene glycol (PEG), as verified by thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. Scanning electron microscopy (SEM) images show that the FCNTs are homogeneously dispersed in the Nafion matrix. The properties of FCNT–Nafion composites in terms of water uptake, ion exchange capacity, proton conductivity, dynamic mechanical properties, and actuation behavior were evaluated. The results show that the sample with 0.5 wt% FCNT exhibits the best overall behavior. Its storage modulus is 2.4 times higher than that of Nafion. In addition, the maximum generated strain and the blocking force for the same sample are 2 and 2.4 times higher compared to the neat Nafion actuator, respectively.

Electro-active graphene–Nafion actuators

Electro-active actuators based on graphene reinforced Nafion composite electrolytes were developed and their electro-chemo-mechanical properties and actuation performances were investigated. The tensile strength of the graphene–Nafion ionic membrane was significantly improved up to 200% within 1.0 wt.% loading, and Young’s modulus was more than two times with a minute loading of graphene to Nafion electrolyte. The proton conductivity and the water-uptake ratio were greatly improved, while apparent changes in the ion exchange capacity were not observed. Morphological tests, chemical techniques, and scattering techniques were used to study the interaction mechanism between graphene and Nafion, resulting in great improvements of the actuation performances. Present results show that a minute loading of graphene greatly improves the harmonic responses, the blocking force and the energy efficiency in Nafion-based ionic polymer–metal composite actuators.

Electrochemical Response of Polymer Actuators using Finite Element Formulation and ANSYS/Emag

The two-dimensional finite element formulation for the basic field equations governing electrochemical responses of ionic conducting polymer-metal composite(IPMC) actuators is proposed in the present study. Biaxial deformation of a platinum plated Nafion actuator having 4 electrodes is dominated by electro-osmosis of hydrated ions and self-diffusion of free water molecules. Some numerical studies for IPMC actuators with electric field are carried out in order to show the validity of the proposed formulation and electric field analysis for the initial condition of total charge distribution are conducted using commercial code ANSYS/Emag.

Fabrication and actuation of electro-active polymer actuator based on PSMI-incorporatedPVDF

In this study, an ionic networking membrane (INM) of poly(styrene-alt-maleimide)(PSMI)-incorporated poly(vinylidene fluoride) (PVDF) was applied to fabricateelectro-active polymer. Based on the same original membrane of PSMI-incorporatedPVDF, various samples of INM actuator were prepared for different reduction times withthe electroless-plating technique. The as-prepared INM actuators were tested in terms ofsurface resistance, platinum morphology, resonance frequency, tip displacement, currentand blocked force, and their performances were compared to those of the widely usedtraditional Nafion actuator. Scanning electron microscopy (SEM) and transmissionelectron microscopy (TEM) revealed that much smaller and more uniform platinumparticles were formed on the surfaces of the INM actuators as well as within theirpolymer matrix. Although excellent harmonic responses were observed for the newlydeveloped INM actuators, they were found to be sensitive to the applied reductiontimes during the fabrication. The mechanical displacement of the INM actuatorfabricated after the optimum reduction times was much larger than that of itsNafion counterpart of comparable thickness under the stimulus of constant andalternating current voltage. The PSMI-incorporated PVDF actuator can become apromising smart material to be used in the fields of biomimetic robots, biomedicaldevices, sensors and actuator, haptic interfaces, energy harvesting and so on.

Finite Element Analysis of Two-Dimensional Electrochemical-Mechanical Behaviors of Ionic Conducting Polymer Actuators

The two-dimensional finite element formulation for the basic field equations governing electrochemical responses of ionic conducting polymer-metal composite (IPMC) actuators is proposed in the present study. Biaxial bending deformation of a platinum plated Nafion actuator having 4 electrodes is dominated by internal water redistribution, which is associated with electroosmosis of hydrated ions and self-diffusion of free water molecules. Two processes can be considered separately in the way that fast electroosmosis is followed by much slower self-diffusion. Some numerical studies for IPMC actuators with several types of electric field are carried out in order to show the validity of the proposed formulation.

Finite Element Modeling of Electrochemical-Mechanical Behaviors of Ionic Conducting Polymer-Metal Composites

Bending deformation of an ionic conducting polymer-metal composite (a platinum plated Nafion) upon applied low electric field across its thickness is dominated by internal water redistribution. Internal water redistribution is associated with two phenomena, electroosmosis of hydrated ions and self-diffusion of free water molecules. Two processes can be considered separately in the way that fast electroosmosis is followed by much slower self-diffusion. Consequently, there is strain distribution due to different water content throughout the thickness. In the present study, finite element formulation is conducted for the basic field equations governing electrochemical-mechanical response of a platinum plated Nafion actuator upon applied electric field. Some numerical studies are carried out in order to show the validity of the present formulation.

918 IPMC アクチュエータの電気化学・力学挙動の有限要素解析

Bending deformation of an ionic conducting polymer-metal composite (a platinum plated Nafion) upon applied low electric field across its thickness is dominated by electroosmosis of hydrated ions and self-diffusion of free water molecules. Two processes can be considered simultaneously. Consequently, there is strain distribution due to different water content throughout the thickness. In this study, finite element formulation is conducted for the basic field equations governing electro-chemo-mechanical response of a platinum plated Nafion actuator upon applied electric field.