Biomimetic Insights: Structure-Toughness Relations in Spider Silk Nanocrystals
This brief communication proposes reasons for why larger β-sheet nanocrystals in spider silk exhibit lowered toughness as a function of increasing lateral size, but higher toughness as the β-strands are lengthened. Herein, this phenomenon is understood to be due to β-sheet stacking and the non-linear decreases in the electrostatic forces of attraction between β-sheets as more sheets are conjoined to form the crystal. Lengthening the β-strands raises the crystal toughness as a result of heightened electrostatic forces of attraction between the sheets. The extent of β-sheet nanocrystal toughness is a fractional balance between inter- and intramolecular bond strengths.
P. Alam, "Biomimetic Insights: Structure-Toughness Relations in Spider Silk Nanocrystals", Advanced Materials Research, Vols. 622-623, pp. 1799-1802, 2013