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Lee J.-W.,Artificial Muscle Research Center | Lee J.-W.,Konkuk University | Kim J.-H.,Artificial Muscle Research Center | Kim J.-H.,Konkuk University | And 5 more authors.
Journal of Bionic Engineering | Year: 2010

Partially crosslinked and sulfonated poly(vinyl alcohol) (s-PVA) membranes were prepared as ion-conductive matrices of Ionic Polymer-Metal Composite (IPMC) and a new IPMC based on the s-PVA membrane was fabricated via an electroless plating procedure of platinum. PVA was reacted with sulfosuccinic acid (SSA) as a crosslinking agent with a sulfonic group and 4-(2-hydroxyethyl)piperazine-1-propanesulfonic acid (EPPS) as a side chain with a sulfonic group. The crosslinked s-PVA membranes were characterized using a FT-IR spectroscope and a scanning electron microscope-combined energy-dispersive X-ray spectrometer and were assessed in terms of water absorption, proton conductivity, and the feasibility of electroless plating. Among the prepared ionomers, the s-PVA membrane obtained at 20 wt.% SSA and 10 wt.% EPPS (S20E10 membrane) registered the highest proton conductivity of 2.9 × 10-2 S·cm-1, which corresponds to one third of that of Nafion series, and only the S20E10 membrane was successfully plated via the electroless plating method without any crack and broken part. The s-PVA-based IPMC showed the one-directional displacement with 1-minute-long time-lapse comparable to typical Nafion-based IPMCs. However, the displacement under an AC potential was very limited due to its slow deformation response and the actuation performance was severely varied with actuation time including the short service life of several minutes in air. The short and variable actuation of the s-PVA-based IPMC was attributed to its large variation of surface and ionic resistances during air-operation, which is induced by the low ratio of bound to free water. © 2010 Jilin University.


Luqman M.,Artificial Muscle Research Center | Lee J.-W.,Artificial Muscle Research Center | Lee J.-W.,Konkuk University | Moon K.-K.,Artificial Muscle Research Center | And 3 more authors.
Journal of Industrial and Engineering Chemistry | Year: 2011

Herein, we report the actuation performance of a cost-effective sulfonated polystyrene (sPS)-based IPMC, and its comparison with that of a Nafion-based IPMC. It was observed that the current density (810 vs. 456mA/cm2), the tip displacement (ca. 44 vs. 23mm), the response rate (ca. 10.3 vs. 2.9mm at starting 3s) and the blocking force (ca. 2.76 vs. 1.51gf) were significantly higher for the sPS-IPMC compared to those for the Nafion-IPMC. Additionally, the sPS-IPMC showed very slow back relaxation. With the aid of the scanning electron microscopy for the morphological analysis and various methods for quantitative analysis, we found that the excellent electromechanical response of the sPS-IPMC was due to the smoother and thicker electrode layer, the higher tensile modulus, the enhanced hydraulic force based on the higher water uptake and higher ion exchange capacity (IEC) value than those of the Nafion-IPMC. The sPS-based IPMCs seem to be one of the promising alternatives of the conventional expensive IPMCs. © 2010.

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