The Structure of Silkworm Silk

In order to functionalize silk fibers without disturbing their performance, the structure of silk fibers needs to be understood. Although the Bombyx mori silkworm silk structure has been investigated for some time, the hierarchical structure did 

The density of raw silk fibers is about 1.33-1.45 g cm . Raw cocoon silk fibers have good extensibility (25-35%) and reasonably good strength (300-600 MPa). For different silkworms, silk properties also are very different Some silk has strong mechanical properties, and other silk shows good biodegradabihty. The structure of the different types of silk has become a research focus. Recently, the diversity of test instruments is also facilitating the study of silk structure [21, 22]. 

To characterize the structure of silk, various techniques, namely X-ray diffraction (XRD), vibrational spectroscopy, and cross-polarization magic-angle spinning nuclear magnetic resonance, and so on, have been adopted. Hu et al. reported a study of self-assembled yS-pleated sheets in Bombyx mori silk fibroin films using 

Recently, Liu and his groups combined XRD, Fourier transform infrared (FTIR) spectroscopy, scanning electronic microscopy/transmission electronic microscopy, AFM, and computer simulations, to examine the hierarchical structures of both silkworm and spider silks [34-36]. 

Correspondingly, AFM and scanning electron microscope (SEM) results show that both spider and silkworm silk fibers are composed of numerous nano fibrils of diameter about 20-30nm, which are separated into crystalline and non-crystalline 

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