Structure evolution of spider silk liquid crystalline precursor material

摘要

Spiders produce silk fibers with remarkable mechanical properties using an ultra-optimized spinning process. The fluid precursor material used to draw the silk threads is a lyotropic nematic liquid crystal. The mechanical properties of the silk fibers as well as their processability are strongly affected by the complex structural transitions undergone by the nematic liquid crystal precursor along the spinning line. Our work focuses on the particular structure adopted by the nematic precursor in the extrusion duct of the spinning apparatus. This structure is characterized by a succession of well denned point defects located on the axis of the cavity and interacting on each other through elastic mediated forces. The phenomenon described is both important in understanding the process-induced structuring of spider silk fibers and to defect physics.