Synthesis and optical properties of blue pigment CoAl2O4 nanofibers by electrospinning

•Blue pigments CoAl2O4 nanofibers were synthesized by electrospinning for the first time.•The nanofibers with diameter ranging from 235 to 542 nm were obtained at different temperatures.•The high calcination temperatures are strongly enhanced blue pigments. Blue pigment cobalt aluminate (CoAl2O4) nanofibers were successfully synthesized for the first time by electrospinning combined with calcination of polyacrylonitrile/cobalt nitrate/aluminum acetylacetonate composite fibers at 700–1000 °C in air. The blue CoAl2O4 nanofibers were characterized by XRD, FE-SEM, UV–vis DRS, and CIE L*a*b* color measurement. XRD results confirmed that diffraction peaks corresponded to CoAl2O4 phase with good crystallinity. FE-SEM images revealed that the calcined nanofibers had rough surfaces with fiber diameter ranging from 235 to 542 nm. The CIE L*a*b* color measurement suggested that blue color (-b) and Chroma C* value improved and calcination caused the pigment to become brighter and bluer.