“…In addition, the nanofibers had a uniform fiberdiameter for each polymer concentration, and the mean diameters of the nanofibers at 12, 15, and 18 wt% polymer concentrations were 77 AE 11, 102 AE 19, and 157 AE 11 nm (n ¼ 25), respectively. We succeeded in preparing g uniaxially aligned non-beaded nanofibers as compared to those fabricated from the six-membered ring polyimides reported in our previous reports [27] by using 6FDA-BDSAr-APPF, which possesses more flexible structure and a good solubility for organic solvents. In addition, we also succeeded in preparing an ultrafine and uniform nanofiber with a diameter of less than 100 nm by using the 6FDA-BDSA-r-APPF, although the nanofibers fabricated from the six-membered ring polyimides indicated a diameter of more than 200 nm [27].…”