Figure 7.
Morphology and secondary structure changes of silk films prepared through slow drying following degradation: (A) SEM images of fracture surface of silk film explosion to protease XIV solution for 6h (a–c) and 12h (d–e): (a) Globule structure at low magnification. The white arrow indicates the direction from the surface to the inside; (b) Nano-structures near the surface area of silk films at higher magnification; (c) Nano-structures inside of the silk films at higher magnification; (d) Globule structure at low magnification, incubation time 12 h; and (e) Nano-structure at higher magnification, incubation time 12h. (B) Secondary structure changes with degradation time. The content of secondary structures was calculated from the deconvoluted amide I band using the method of Fourier self-deconvolution. N=3, bars represent standard deviation.