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.
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.
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.