Synchrotron FTIR Microspectroscopy Methods to Understand the Conformation of Single Animal Silk Fibers.

Animal silks have received extensive attention in these years due to their unique mechanical properties. The study of the structure-property relationship of animal silks is not only critical for the understanding of the design secrets of natural materials but also can inspire the engineering material designs. Fourier transform infrared spectroscopy (FTIR) has been used to study the secondary structure of animal silk, which is considered to be critical to the mechanical properties of animal silk. However, most of these characterizations are conducted on silk fiber bundles. In this respect, synchrotron FTIR microspectroscopy (S-micro FTIR) has unique advantages in characterizing single animal silks, as S-micro FTIR has significant advantages in ultrahigh brightness and high spatial resolution to characterize samples with small size. Here, we will introduce the methods for using synchrotron FTIR microspectroscopy to analyze the conformation and orientation of single animal silk fibers, which would be an efficient method to elucidate the "structure-property" relationship within animal silks.