Polypyrrole-wool composite with electrical heating properties fabricated via layer-by-layer method

Abstract

Conductive polymer-textile composites with electric heating features were developed by the in-situ polymerization of polypyrrole on wool-felt fabrics. In particular, the amount and uniformity of polypyrrole deposition inside the fabrics was controlled by consecutive cycles of layer-by-layer (LBL) in-situ polymerization. To analyze the interaction principle of wool fiber and polypyrrole and to explore the processing conditions that can maintain the mechanical properties of the composites, the appearance, add-on, and electrical heating performance were evaluated according to the number of LBL cycles. The polypyrrole formed spherical particles on the wool-felt after polymerization. As the number of LBL cycles increased, more polypyrrole particles were deposited. In the case of mechanical properties, the tensile strength and bending rigidity increased with the polypyrrole deposition, and the strain decreased; however, the difference according to the number of LBL cycles was insignificant. However, the electrical properties were implemented in the polypyrrole-wool composites by polymerization, and a rapid decrease in the surface resistance was observed until the second LBL cycle. In the case of electrical heating performance, the surface temperature increased by up to 15.5 ℃ when 12 V voltage was applied, and the surface temperature increased linearly as the number of LBL cycles increased. This electrical heating performance maintained a high temperature for a certain period, even after removing the voltage, owing to the low thermal conductivity of the wool fiber. In addition, the polypyrrole conductive layer maintained excellent conductivity even after repeated abrasion owing to the improvement in uniformity by the LBL cycles.