Soft capacitor fibers using conductive polymers for electronic textiles

Abstract

A novel, highly flexible, conductive polymer-based fiber with high electric capacitance isreported. In its cross section the fiber features a periodic sequence of hundreds of conductiveand isolating plastic layers positioned around metallic electrodes. The fiber is fabricatedusing the fiber drawing method, where a multi-material macroscopic preform is drawn intoa sub-millimeter capacitor fiber in a single fabrication step. Several kilometers of fibers canbe obtained from a single preform with fiber diameters ranging between 500 and1000 µm. A typical measured capacitance of our fibers is60–100 nF m−1 and it is independent of the fiber diameter. Analysis of the fiber frequency response showsthat in its simplest interrogation mode the capacitor fiber has a transverse resistance of5 kΩ m L−1, which is inversely proportional to the fiber lengthL and is independent of the fiber diameter. Softness of the fiber materials, the absence ofliquid electrolyte in the fiber structure, ease of scalability to large productionvolumes and high capacitance of our fibers make them interesting for varioussmart textile applications ranging from distributed sensing to energy storage.