Abstract: A series of poly(L-lactic acid)(PLLA) three-dimensional(3D) nanofibrous scaffolds were fabricated by phase separation from a ternary PLLA/dioxane/tert-butanol system. The effects of aging process, aging temperature, polymer concentration, the ratio of dioxane and tert-butanol on the morphology of scaffolds and the diameter of fibers were investigated. The results show that aging process played a crucial role in forming the unique nanofibrous structure in a lower polymer concentration(≤7%). However, the nanofibrous structure was also obtained by control phase separation in a certain extend of temperature in a higher polymer concentration(≥10%). A lower aging temperature(≤5℃) was proved to be helpful for forming nanofibrous scaffold(diameter of fiber:20-300nm), and the nanofibrous network structure was more uniform as the temperature becomes lower. Furthermore, the fibers become thinner and the nanofibrous network becomes more uniform with increasing the polymer concentration, at the same time the pore morphology tends to be denser. The diameter of fibers did not change statistically when the content of tert-butanol is less than 12%, but it changed obviously, even reached up to 500nm when the content of tert-butanol is more than 12%.

Key words: nanofibrous, phase separate, aging, poly(L-lactic acid), tertiarybutanol