Ionic polymer-metal composite bending actuator loaded with multi-walled carbon nanotubes

Multi-walled carbon nanotube (M-CNT)/Nafion nanocomposites were prepared by the dispersion of treated M-CNTs in a Nation solution; this procedure was done in order to evaluate the influence of M-CNT loading of up to 7 wt.% on the M-CNT distribution behavior, mechanical properties, and the related actuation performance of the composites. As the M-CNT loading rose above I wt.%, the uniformly distributed M-CNT bundles induced by the Nafion polymer were determined to be perturbed, resulting in an inhomogeneous distribution. The heterogeneously distributed M-CNT bundles may provide an undesired impact on the connectivity within the Nation membrane, thus giving rise to the poor electrochemicallygenerated actuation properties. It is important to note that the nanocomposite having only a 1 wt.% of M-CNT loading exhibited the best actuation performance in terms of the blocking forces produced by the M-CNT nanocomposites in a cantilever form. It can be understood that the performance improvement is caused by the uniform distribution of the M-CNT bundles, which was confirmed by TEM, XRD and electromechanical actuation tests. It is concluded that the M-CNT distribution behavior, induced by interactions between the polymer matrix, Nafion and the M-CNTs and the related electromechanical performance of the composites, are mainly governed by the M-CNT content. Also, DMA testing was performed. (c) 2006 Published by Elsevier B.V.