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A pH sensitive polyacrylonitrile (PAN) fiber, exhibiting soft actuation as a linear actuator, is prepared by electrospinning to investigate the optimum experimental condition of the as-spun fibers and the effect of pH variation on length change of PAN gel fiber. Unbeaded smooth and continuous PAN nanofibers with diameter of ~700 nm are obtained for the 10 wt% PAN fibers at a flow rate of 0.5 mL/h and an electric field of 0.875 kV/cm, suggesting that the value of viscosity is the most significant on the fiber morphology. Diameter and volume changes of PAN filaments are observed as greater than 100% and greater than 720%, respectively for pH activated systems. A typical hysteresis loop is observed for the length change (~38%) of PAN gels with respect to pH variation.

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New types of functional thin films of Cr-Si and Ni-Si were fabricated for heating element applications. In order to reduce the problem of large variations of electrical resistance of heating elements during the semiconductor thermal processing, we attempt to minimize temperature coefficient of resistance (TCR) of the heating material by mixing the semiconductor and metallic materials. As the heating elements, two different multi-layered structures were prepared by RF magnetron sputtering technology; Cr-Si and Ni-Si structures on top of Al 2 O 3 substrates. The thickness of the Cr-Si and Ni-Si films ranged up to a couple of micron, and a post annealing at 750°C was carried out to achieve more reliable film structures. The electrical and thermodynamic properties of the thin films were measured up to the temperature of 500°C. Chrome-rich films show the metallic properties, whereas silicon-rich films do the semiconductor properties in measurements of TCR. Optimal composition between chrome and silicon has been obtained as 2:1 in the Auger electron spectroscopy analysis. TCR for the sample was estimated as about +0.0003/°C -1 , which is fairly low value when considering the conventional heating elements.

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