Ultra-fine polyimide fibers containing silver nanoparticles were prepared by electrospinning from poly(amic acid)/(trifluoroacetylacetonoto) silver(I) (PAA/AgTFA) solution. Thermal curing of the silver(I)-containing fibers led to cycloimidization of the poly(amic acid) into polyimide with concomitant silver(I) reduction. The polyimide-silver fibers were characterized by FT-IR, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The average diameters of silver nanoparticles and ultra-fine PI fibers electrospun from solutions with different amounts of AgTFA were studied, and the crystal structure of silver nanoparticles was also presented. (c) 2007 Elsevier B.V All rights reserved.