The researchers investigated the influence of the first drawing step of their fiber regeneration using solid-state NMR spectroscopy. NMR spectra were deemed the most suitable methods for analyzing a series of spectra from single-drawn regenerated silk samples. The spectra were recorded and samples differed only in that the length of the post-spinning draw was varied for each. To demonstrate the fundamental effect of drawing on the spider silk protein structure, the team exploited the dependence of the chemical shift of 13 C atoms on the local conformation of the protein. They are determined by the post-spinning processing.
Water acts to plasticize the silk fibroin and stabilize the processing.
Materials scientists hoping to reproduce the spider silk's strength could do worse than to bear that in mind.