Consecutive large-scale fabrication of surface-silvered polyimide fibers via an integrated direct ion-exchange self-metallization strategy.

Herein, we report our success on the large-scale online preparation of surface-silver-metallized polyimide (PI) fibers by utilizing silver ammonia complex cation ([Ag(NH3)2]+) as the silver (Ag) precursor and pyromellitic dianhydride/4,4′-oxidianiline (PMDA/4,4′-ODA)-based polyimide as the matrix via a direct ion-exchange self-metallization process integrated within a consecutive fiber-spinning procedure. The method works by using the online freshly prepared PMDA/4,4′-ODA-based poly(amic acid) (PAA) fibers as the starting material to perform an ion-exchange reaction in aqueous silver(I) solution to load silver(I) into the PAA precursor fibers, followed by a programmed stepwise thermal treatment process to convert PAA to its final imide form with the concomitant silver(I) reduction and the subsequent aggregation, producing the surface-silvered polyimide hybrid fibers. The influence of thermal cycles on the formation of silver nanostructures, and the variation of surface morphologies and fiber properties du...