Fig. 2
From: Polymorphic regenerated silk fibers assembled through bioinspired spinning
Visual appearance and structural characterization of the regenerated silk spinning dope and resultant RSFs. a–c Visual appearance (a), polarized light microscopy image (b), and SEM image (c) of B. mori silk fiber /HFIP mixture with a weight ratio of 1:20 after incubation at 60 °C for 15 days. After 15 days the silk fiber partial dissolved to microfibrils with diameters of 5–10 µm and contour lengths of several hundreds to thousands of micrometers. The resultant SMF/HFIP mixture was a uniform, highly viscous solution with nematic liquid-crystal-like texture. d The photograph to show the facile bioinspired spinning process. The nematic SMF/HFIP solution can be directly reeled to form RSFs. e, f Visual appearance (e) and polarized light microscopy image (f) of as-spun RSFs. g–i SEM images of as-spun RSFs. The images h and i are a top view and cross-sectional SEM images of RSF, respectively. The RSF is constituted by highly oriented and bound SMFs. The inset of the image i is high-resolution SEM image of a cross-section of RSF. Well-organized silk nanofibrils are observed. False color is used in SEM images. Scale bars, 50 µm (b), 200 µm (c), 100 µm (f), 200 µm (g), 20 µm (h), 20 µm (i), and 2 µm (inset of i)
