Functionalizing Poly(3-hexylthiophene) as a Naked-eye Discharge Indicator for High Voltage Applications

Abstract

Polymeric insulating structures in power equipment inevitably deteriorate under long-term operation, initiating unobservable partial discharge, which develops into breakdown and insulation failure, resulting in large-area power shutdown, causing huge economic losses. Currently, detection of early discharge relies on optical fiber sensing, ultrasound etc., which requires additional electrical signal access or complexed equipment. Herein, poly(3-hexylthiophene) (P3HT) is functionalized as a flexible naked-eye discharge indicator through color changes by discharge triggered oxidation. The high voltage discharge generates active oxygen radicals, which oxidize Hα on P3HT side-chain and Cα on the thiophene ring, leading to breakage of the side-chain and backbone, as well as thiophene ring open, resulting in crystallinity changes from highly regular edge-on to amorphous configuration, giving rise to observable color change. The vertical dielectric performances of P3HT and typical non-conjugated polymer composite films are highly sustained, which is further potentially applied in quantitative evaluation of fault discharge in a power cable branch box under operation. Based on the worldwide huge amount of power equipment, this approach may not only board the application of P3HT in power industry, but could bloom the demands of such conjugated polymers from organic electronics towards massive applied commodity chemicals.