Ionic Polymer-Metal Composite Actuators Based on Nafion Blends with Functional Polymers

摘要

Ionic polymer metal composites (IPMCs) have been an attractive research subject for use in underwater robotic applications, biomedical and biomimetic application owing to their great potential as actuators, artificial muscles, and more. IPMC is synthetic composite nanomaterial of ion exchange membranes and metal electrode. Although both components are important, the properties of ion exchange membranes should be emphasized since it is responsible of the path for the mobile ions to migrate when voltage is applied to exhibit deformation. Most of the researches that have been done on IPMCs used commercially available Nafion as their ion exchange membranes. However, its high cost, limitations in thermal and mechanical properties are some of the disadvantages that needs to be modified. In this thesis, we chose two different polymers, poly(vinyl alcohol-co-ethylene) [P(VA-co-E)] and polyimide [PI], as blending partners of Nafion in order to overcome these disadvantages while maintaining high ionic conductivity. In chapter 2, blend ion exchange membranes of Nafion and P(VA-co-E) were casted using physical blending method. The membranes were characterized by Fourier transform infrared spectroscopy and differential scanning calorimetry. IPMCs based on these membranes were fabricated by deposition of platinum electrode onto their surface via electroless plating process. The electrode surface of prepared IPMCs was measured using two point probe method. The cross-sectional morphologies of the IPMCs were characterized through Scanning electron microscopy and Energy-dispersive X-ray spectroscopy analysis was done. The electromechanical performances (displacement and blocking force) of the prepared IPMC actuators were further characterized. In chapter 3, blend ion exchange membranes of Nafion and PI were obtained by casting of Nafion and poly(amic acid) [PAA]membranes and the following thermal imidization. Same characterizations were done as in chapter 3. The IPMC actuators with the blend Nafion membranes demonstrated comparable electromechanical performance to the Nafion membrane by either lowering the manufacturing cost or improving thermal and mechanical properties.