The effect of solvents on spider silk studied by mechanical testing and single-fibre Raman spectroscopy

We used well-defined, fluorescence-free Raman spectra of single silk fibres to study silk ultrastructure. Major ampullate (MA) silk was reeled from th e Araneus diadematus spider under controlled conditions. With a custom-buil t stress-strain gauge, we examined the mechanical properties of this silk b oth before and after supercontraction in a range of solvents. The solvents were found to modify the material properties considerably. We suggest that the solvents with their different polarities affect different regions of th e silk's composite microstructure, in particular the conformation of the mo lecular chains. (C) 1999 Elsevier Science B.V. All rights reserved.