폴리비닐 부티랄에 붙힌 지르코늄 알콕시드 졸을 사용한 전기방사에서 지르코니아 나노섬유 제조와 광발광

Abstract

A zirconia gel/polymer hybrid nanofiber was produced in a nonwoven fabric mode by electrospinning a sol derived from hydrolysis of zirconium butoxide with a polyvinyl butyral. Results indicated that the hydroxyl groups on the vinyl alcohol units in the backbone of the polymer were involved in the hydrolysis as well as grafting the hydrolyzed zirconium butoxide. In addition, use of acetic acid as a catalyst resulted in further hydrolysis and condensation in the sol, which led to the growth of -Zr-O-Zr- networks among the polymer chains. These networks gradually transformed into a crystalline zirconia structure upon heating. The as-spun fiber was smooth but partially wrinkled on the surface. The average fiber diameter was 690±110 ㎚. The fiber exhibited a strong but broad blue photoluminescence with its maximum intensity at a wavelength of ~410 ㎚ at room temperature. When the fiber was heat-treated at 400℃, the fiber diameter shrunk to 250±60 ㎚. Nanocrystals which belonged to a tetragonal zirconia phase and were ~5 ㎚ in size appeared. A strong white photoluminescence was observed in this fiber. This suggests that oxygen or carbon defects associated with the formation of the nanocrystals play a role in generating the photoluminescence. Further heating to 800℃ resulted in a monoclinic phase beginning to form In the heat-treated fibers, coloring occurred but varied depending on the heating temperature. Crystallization, coloring, and phase transition to the monoclinic structure influenced the photoluminescence. At 600℃, the fiber appeared to be fully crystallized to a tetragonal zirconia phase.