High-Performance PEDOT:PSS/Single-Walled Carbon Nanotube/Ionic Liquid Actuators Combining Electrostatic Double-Layer and Faradaic Capacitors

New hybrid-type poly­(3,4-ethylenedioxythiophene) (PEDOT) actuators produced by the film-casting method, in which both electrostatic double-layer (EDLC) and faradaic capacitors (FCs) occur simultaneously, have been developed. The electrochemical and electromechanical properties of PEDOT:poly­(4-styrenesulfonate) (PSS), PEDOT:PSS/ionic liquid (IL), and PEDOT:PSS/single-walled carbon nanotubes (SWCNTs)/IL actuators are compared with those of a conventional poly­(vinylidene fluoride)-<i>co</i>-hexafluoropropylene (PVdF­(HFP))/SWCNT/IL actuator. It is found that the PEDOT:PSS/SWCNT/IL actuator provides a better actuation strain performance than a conventional (PVdF­(HFP))/SWCNT/IL actuator, as its electrode is an electrochemical capacitor (EC) composed of an EDLC and FC. The PEDOT:PSS polymer helps produce a high specific capacitance, actuation strain, and maximum generated stress that surpass the performance of a conventional PVdF­(HFP) actuator. The flexible and robust films created by the synergistic combination of PEDOT and SWCNT may therefore have significant potential as actuator materials for wearable energy-conversion devices. A double-layer charging kinetic model was successfully used to simulate the frequency dependence of the displacement responses of the PEDOT:PSS/IL and PEDOT:PSS/SWCNT/IL actuators

Self-Sensing Ionic Polymer Actuators: A Review

Ionic electromechanically active polymers (IEAP) are laminar composites that can be considered attractive candidates for soft actuators. Their outstanding properties such as low operating voltage, easy miniaturization, and noiseless operation are, however, marred by issues related to the repeatability in the production and operation of these materials. Implementing closed-loop control for IEAP actuators is a viable option for overcoming these issues. Since IEAP laminates also behave as mechanoelectrical sensors, it is advantageous to combine the actuating and sensing functionalities of a single device to create a so-called self-sensing actuator. This review article systematizes the state of the art in producing self-sensing ionic polymer actuators. The IEAPs discussed in this paper are conducting (or conjugated) polymers actuators (CPA), ionic polymer-metal composite (IPMC), and carbonaceous polymer laminates

Actuation and blocking force of stacked nanocarbon polymer actuators

We have developed stacked nanocarbon polymer actuators that are composed of several nanocarbon polymer actuator films using nonwoven fabric as insulation layers. The nonwoven fabric prepared through electrospinning methods has extremely-low-density structures, which do not significantly prevent the motions of each nanocarbon actuator layer. Therefore, stacking several thin nanocarbon polymer actuators using nonwoven fabric as insulation layers is expected to increase generated force without decreasing the displacement of a one-layer actuator. We have prepared stacked actuators with one, two, three, four, and seven layers using this method. The displacement and blocking force of these actuators are measured and compared with those of one-layer actuators of different thicknesses. Displacement is weakly dependent on the thickness of the actuator films of the stacked actuators. On the contrary, it decreases considerably as the thickness of the actuator film of the one-layer actuator increases. In both cases, blocking force is proportional to the thickness of actuator films. We have developed a stacked actuator model based on a trilayer actuator model and confirmed the experimental results using the model

Distributed parameter system modeling of IPMC actuators with the electro-stress diffusion coupling theory

ABSTRACT Toward the construction of the unified model of ionic polymer actuators, this paper discusses the system modeling with the electro-stress diffusion coupling theory. The theory can explain the differences of the relaxation phenomenon of polymer electrolytes with respect to the various counter ion species in the polymer. In addition to the mechanical system which employs a simple beam model, the electrical system and the electro-mechanical coupling systems are also represented by partial differential equations. The electrical system is modeled based on the non-uniform distributed circuit which represents the electrode roughness. The electro-mechanical coupling system is derived from the electro-stress diffusion coupling theory. The overall system is represented by a statespace equation with a feedback structure. The comparisons between the simulation result and the experimental result show the validity of the model

Recent advances in ionic polymer–metal composite actuators and their modeling and applications

This paper presents a comprehensive review of ionic polymer–metal composite (IPMC) actuators. Recently, strong emphasis has been put on investigating various ionic polymer membranes for high-performance IPMC actuators and overcoming some drawbacks of ionic polymer actuators to improve stability and reliability. The paper gives an overview of different types of sulfonated ionic polymer membranes. Various emerging materials that exhibit notably good deformation, stability, and efficiency are extensively considered. A thorough comparison of different state-of-the-art ion exchange membranes is presented. Along with the material study, recent trends in modeling and control approached of IPMC actuators are presented. Although fundamental models of IPMC were proposed over a decade ago, physics-based models are still being developed in order to study specific aspects of the actuators and to develop a control design for practical applications. Therefore, this paper considers the latest actuation models and control designs of IPMC actuator and various promising prototype applications that lead the way in using the materials for real applications in future