In this study, a highly stable air-operating ionic polymer-metal composite (IPMC) actuator with consecutive channels suitable for transportation of the cations and anions of ionic liquids was prepared by introducing and removing copper foam. The electromechanical properties of this novel porous IPMC were investigated. Scanning electron microscopy observation showed that channels and pores ranging in size from ∼100 nm to ∼50 μm were distributed in the Nafion membrane. The porous IPMC was doped with 1-ethyl-3-methylimidazolium thiocyanate ionic liquid. A larger capacitance (285.00 mF cm −2 ) was obtained, which can be attributed to the electric double layer generated at the interface between the ionic polymer membrane and platinum electrode under the input voltage. The fast ion migration channels, high conductivity, and large capacitance enabled high strain of 0.051%-0.666%, a relatively large blocking force of 17.63 mN, and excellent actuation durability for more than 180 000 cycles to be achieved. Furthermore, a soft gripper consisting of a bio-inspired micropillar dry adhesive glued on one surface of the porous IPMC assembled with a mobile mechanical arm was fabricated, and the soft gripper successfully grabbed objects with various features.

Recently, researchers have concentrated on studying ionic polymer metal composite (IPMC) artificial muscle, which has numerous advantages including a relatively large strain under low input voltage, flexibility, high response, low noise, light weight, and high driving energy density. This paper reports recent developments in IPMC artificial muscle, including improvement methods, modeling, and applications. Different types of IPMCs are described, along with various methods for overcoming some shortcomings, including improvement of Nafion matrix membranes, surface preparation of Nafion membranes, the choice of high-performing electrodes, and new electro-active polymers for enhancing the properties of IPMCs. IPMC models are also reviewed, providing theoretical guidance for studying the performance and applications of IPMCs. Successful applications such as bio-inspired robots, opto-mechatronic systems, and medical engineering are discussed.

Ionic polymer-metal composite (IPMC) is an electro-active polymer material, which has many advantages such as small size, light weight, low driving voltage, large strain, and good biocompatibility. However, the conventional sheet IPMC has the shortcoming of only bending in the two-dimensional plane, which greatly limits the application of IPMC in the field of interventional surgery. In this work, a square rodshaped IPMC with multi-degree-of-freedom motion was fabricated, and the displacement and blocking force of the square rod-shaped IPMC in different directions are measured and analyzed under the DC voltage signal. An interventional catheter was designed using the square rod-shaped IPMC in order to achieve active guidance, and a simulation experiment platform and a model of human aorta were built to successfully complete the in vitro simulation experiment of interventional surgery, which preliminarily verified the feasibility of the square rod-shaped IPMC in the field of interventional surgery.

Hydrothermal reactions of benzene-1,3,5-triyltris(methylene)triphosphonic acid (H 6 L 1 ) or (2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene)triphosphonic acid (H 6 L 2 ) with metal sulfates, 4,49-bipyridyl (4,49-bipy), 2,29-bipyridyl (2,29-bipy), 1,10-phenanthroline (1,10-phen) and 1,2-di(4-pyridyl)ethylene (dpe), afforded eight new transition metal trisphosphonates, namely, [Cu 2 (H 8). The single-crystal X-ray diffraction measurements indicate that compounds 2 and 8 are isostructural and feature 3D framework structures with (5,6,8)-net topology; 1, 5 and 6 exhibit 2D layered structures; whereas 3, 4 and 7 have 0D dimer structures. The trisphosphonate ligands (H 6 L 1 and H 6 L 2 ) in these eight compounds adopt either cis-cis-cis or cis-trans-trans conformation with or without the existence of an auxiliary N-containing ligand. The attachment of methyl groups to the benzene core can enhance the crystallinity and enrich the structure diversity. The introduction of 2,29-bipy and 1,10-phen usually result in low dimensionality whereas 4,49-bipy can extend the structure to a higher dimensionality. The activated sample of compound 5 has a permanent 1D nanoporous structure and shows high selective adsorption of CO 2 over CH 4 .

In this work, a helical ionic polymer metal composite (IPMC) was fabricated by thermal treatment in a mold with helix grooves. The axial actuation behaviors of the helical IPMC actuator were observed, and the electromechanical and electrochemical characteristics were evaluated. The experimental results showed that as the voltage increased and the frequency decreased, the axial displacement, axial force, and electric current of the actuator all increased. Compared with square wave and sinusoidal signals, the actuator exhibited the most satisfactory motion under the direct current (DC) signal. For the electrochemical test, as the scanning rate decreased, the gravimetric specific capacitance increased. Within a suitable voltage range, the actuator was chemically stable. In addition, we coupled the Electrostatics module, Transport of Diluted Species module, and Solid Mechanics module in COMSOL Multiphysics software to model and analyze the helical IPMC actuator. The simulation data obtained were in good agreement with the experimental data. Finally, by using three helical IPMC actuators as driving components, an innovative three-degree-of-freedom (3-DOF) micro-parallel platform was designed, and it could realize a complex coupling movement of pitch, roll, and yaw under the action of an electric field. This platform is expected to be used in micro-assembly, flexible robots, and other fields.

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Two sodium complexes, [(μ 3-MDBP)Na 2 (THF) 2 ] 2 [(μ 3-OCH 2 CH 2 OCH 3)Na] 2 (1) and [(μ 1-MDBP)Na(μ 2-H 2 O) (THF)] 2 (THF) 2 (2) have been synthesized and structurally characterized. Experimental results show that complex 1 initiates efficiently the ring opening polymerization of L-lactide in a controlled fashion, yielding polymers with narrow polydispersity indexes in a wide range of monomer-to-initiator ratios.

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