Ionic Polymer-Metal Composites (IPMCs) with Various Ion Exchange Membranes and Their Potential Use in IPMC Applications
AdvisorKim, Kwang Jin
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Ionic polymer metal composites (IPMCs) have been widely studied and drawn great attention for the last several years in robotics and medical fields due to their great potential as actuators, artificial muscles, and more. Each part of an IPMC is important, but the role of ionic exchange membrane should be emphasized because, after all, it is where ions migrate when voltage is applied to produce motion. So far, most researches have been done on IPMCs made with commercially available ionic exchange membranes such as Nafion or Flemion. In this thesis, the research is mainly focused on fabricating IPMCs with several other ionic exchange membranes that are commercially available and characterization of optical, physical, and electromechanical properties of those IPMCs. Five different ion exchange membranes of DuPont (N115), Golden Energy Fuel Cells Inc (GEFC-700)., fuMA Tech (F-14100), Membranes International Inc. (CMI-7000S) and University of Nevada Las Vegas (19-PSU-S1) are the chosen membranes. N115, GEFC-700, and F-14100 have the same structure. CMI-7000S is a reinforced membrane by mixing fibers with the ion exchange membrane. 19-PSU-S1 is a membrane that was made at UNLV for fuel cell application. The physical properties of the ionic exchange membranes were studied by examining water uptake. The thermal analysis also was carried out with Differential Scanning Calorimetry (DSC). Water uptake and ion exchange capacities were measured to confirm the physical properties of IPMCs. The structure of the IPMCs was observed under Scanning Electron Microscopy (SEM). The structures of fabricated IPMCs were observed by SEM and DSC. Capacitance was also measured by drawing impedance curves. Young¡¯s modulus (E) was measured to determine the stiffness of each IPMC. Lastly, bending actuation test was carried out to observe the actual performance of each IPMC in water. The water uptake of all IPMCs is less than 40%. 19-PSU-S1 absorbed the most water (35.2 %) and CMI-7000S absorbed the least amount of water (17.1 %). For ion exchange capacity (IEC), 19-PSU-S1 had the largest value of 1.18 meq/g while F-14100 has the smallest as 0.7 meq/g. The glass transition temperatures of all IPMCs were around 100 ¢ªC while it was 87 ¢ªC for 19-PSU-S1. The young¡¯s modulus was the smallest for IPMC with GEFC-700, 169.72 MPa and the largest for one with 19-PSU-S1, 1749.88 MPa. The largest capacitance was observed at the lowest frequency, just above 0 Hz. IPMCs with GEFC-700 and CMI-7000S had the lowest capacitance, 0.06 mF/cm2 and N115 had the largest capacitance, 0.5 mF/cm2. Lastly, the deflection at the tip measured was the largest for the IPMC with N115 and F-14100 while it was the smallest for the IPMC made with GEFC-700. However, deflection at the tip is affected by the thickness. Therefore, bending stain was calculated. GEFC-700S and N117 had very close bending strain value as the largest while CMI-7000S had the smallest. The blocking force is measured and it increased as the stiffness of the IPMCs increase. GEFC-700S had the largest power at 4 V while 19-PSU-S1 had the least power. For all IPMCs, the power was the largest at 1 Hz.