In this paper, we developed a new kind of ionic polymer metal composite (IPMC) actuator by doping sulfonated carbon nanotube (SCNT) into Nafion matrix to overcome some major drawbacks, such as low output force and short air-operation time, which restrict applications of conventional Nafion IPMC actuators. Firstly, SCNT was synthesized by coupled reaction of multi-walled carbon nanotubes and azo compounds and then doped into Nafion matrix by casting method. Subsequently, several key parameters of the SCNT-reinforced Nation matrix, water uptake ratio and equivalent stiffness, were revealed and the inner morphology of the membranes were observed by scanning electron microscopy. Finally, the effects of the SCNT on the electromechanical properties of IPMC actuators, especially the actuating performance, were evaluated experimentally and analyzed systematically. The results showed that SCNT was evenly dispersed in Nafion matrix and a small amount of SCNT could improve the performance of IPMC actuators significantly.
With advantages of low driving voltage, good flexibility and high electromechanical efficiency, ionic polymer-metal composites (IPMCs), which are one of the most attractive smart materials, have been research hotspot in actuators, sensors and artificial muscles. However, a serious drawback of little deformation of thick IPMC actuator limits its application. In this paper, we fabricated thick porous Nafion membranes by freeze-drying process. A series of Thermogravimetric analyses (TGA), Field emission scanning electron microscopy (FE-SEM) and Water uptake (WUP) tests were performed to examine the validity of the freeze-drying process and the pore size and the porosity. Then, the porous IPMCs were fabricated with the freeze-drying processed Nafion membranes by the solution casting and reducing plating. Finally, the IPMC actuators with the dimensions of 25× 5× 1 in millimeters were achieved and tested. The terminal deformation of the porous IPMC actuator increased by 739.7%, compared with the ordinary IPMC actuator with the same dimensions under the driving voltage of 2VDC.
Recently, Ionic polymer metal composites (IPMCs), becoming an increasingly popular material, are used as soft actuators for its inherent properties of light weight, flexibility, softness, especial efficient transformation from electrical energy to mechanical energy with large bending strain response to low activation voltage. This paper mainly focuses on the suitable conditions for surface-roughening of Nafion 117 membrane. The surfaces of Nafion membrane were pretreated and optimized by sandblasting, mainly considering the change of sandblasting time and powder size. The modified surfaces are characterized in terms of their topography from the confocal laser scanning microscope (CLSM) and SEM. Then, the detailed change in surface and interfacial electrodes and performances for IPMC actuators prepared by the roughened membranes, were measured and discussed. The results show that an optimized roughening condition with large interface area (capacitance) can effectively increases the electromechanical responses of IPMC.
With rapid progress of biomedical devices towards miniaturization, flexibility, multifunction and low cost, the restrictions of traditional mechanical structures become particularly apparent, while soft materials become research focus in broad fields. As one of the most attractive soft materials, Ionic Polymer-Metal Composite (IPMC) is widely used as artificial muscles and actuators, with the advantages of low driving-voltage, high efficiency of electromechanical transduction and functional stabilization. In this paper, a new intuitive control method was presented to achieve the omnidirectional bending movements and was applied on a representative actuation structure of a multi-degree-offreedom soft actuator composed of two segments bar-shaped IPMC with a square cross section. Firstly, the bar-shaped IPMCs were fabricated by the solution casting method, reducing plating, autocatalytic plating method and cut into shapes successively. The connectors of the multi-segment IPMC actuator were fabricated by 3D printing. Then, a new control method was introduced to realize the intuitive mapping relationship between the actuator and the joystick manipulator. The control circuit was designed and tested. Finally, the multi-degree-of-freedom actuator of 2 segments bar-shaped IPMCs was implemented and omnidirectional bending movements were achieved, which could be a promising actuator for biomedical applications, such as endoscope, catheterism, laparoscopy and the surgical resection of tumors.
As a new kind of ionic-driven smart materials, ionic polymer metal composite (IPMC ) is normally fabricated by
depositing noble metal (gold, platinum, palladium etc.) on both sides of base membrane (Nafion, Flemion etc.) and
shows large bending deflection under low voltage. In the process of fabricating IPMC, surface roughening of base
membrane has a significant effect on the performance of IPMC. At present, there are many ways to roughen the base
membrane, including physical and chemical ways. In this paper, we analyze the effects of different surface treatment
time by plasma etching on surface resistance and mechanical properties of IPMCs fabricated by the treated base
membranes. Experimental results show that the base membrane treated by plasma etching displays uniform surface
roughness, consequently reducing IPMC’s surface resistance effectively and forming more uniform and homogeneous
external and penetrative electrodes. However, due to the use of reactive gas, the plasma treatment leads to complex
chemical reaction on Nafion surface, changing element composition and material properties and resulting in the
performance degradation of IPMC. And sandblast way should be adopted and improved without any changes on element
and material structure.
Minimally Invasive Surgery (MIS) is receiving much attention for a number of reasons, including less trauma, faster
recovery and enhanced precision. The traditional robotic actuators do not have the capabilities required to fulfill the
demand for new applications in MIS. Ionic Polymer-Metal Composite (IPMC), one of the most promising smart
materials, has extensive desirable characteristics such as low actuation voltage, large bending deformation and high
functionality. Compared with traditional actuators, IPMCs can mimic biological muscle and are highly promising for
actuation in robotic surgery. In this paper, a new approach which involves molding and integrating IPMC actuators into a
soft silicone tube to create an active actuating tube capable of multi-degree-of-freedom motion is presented. First,
according to the structure and performance requirements of the actuating tube, the biaxial bending IPMC actuators
fabricated by using solution casting method have been implemented. The silicone was cured at a suitable temperature to
form a flexible tube using molds fabricated by 3D Printing technology. Then an assembly based fabrication process was
used to mold or integrate biaxial bending IPMC actuators into the soft silicone material to create an active control tube.
The IPMC-embedded tube can generate multi-degree-of-freedom motions by controlling each IPMC actuator.
Furthermore, the basic performance of the actuators was analyzed, including the displacement and the response speed.
Experimental results indicate that IPMC-embedded tubes are promising for applications in MIS.
Ionic Polymer Metal Composites (IPMCs), as one of the most promising smart materials, can produce a large
deformation for low voltage in the range of 0-5V. Since the materials were found, IPMCs have often been studied as
actuators for their large deformation and inherent flexibility. Recently, IPMCs are applied to the optical lens-driving
system. In this paper, we design miniature optical lens actuators for the focusing requirements. And two kinds of the
driving structure, the petal-shaped and annular structure, are proposed. Then, the preparation processes of IPMCs and the
actuators are presented and five kinds of petal-shaped and annular actuators are manufactured and their performances are
tested, respectively. Finally, the performances of the actuators with different parameters are analyzed by an equivalent
thermal model with FEA software.