10.6084/m9.figshare.3811119.v1 Igor Krasnov Igor Krasnov Tilo Seydel Tilo Seydel Imke Greving Imke Greving Malte Blankenburg Malte Blankenburg Fritz Vollrath Fritz Vollrath Martin Müller Martin Müller Supplementary material for the article “Strain-dependent fractional molecular diffusion in humid spider silk fibers” from Strain-dependent fractional molecular diffusion in humid spider silk fibres The Royal Society 2016 spider dragline silk fractional dynamics nanocomposite polymer fibres supercontraction hydrophobic collapse neutron spectroscopy 2016-09-08 06:43:45 Journal contribution https://rs.figshare.com/articles/journal_contribution/Supplementary_material_for_the_article_Strain-dependent_fractional_molecular_diffusion_in_humid_spider_silk_fibers_from_Strain-dependent_fractional_molecular_diffusion_in_humid_spider_silk_fibres/3811119 Spider silk is a material well known for its outstanding mechanical properties, combining elasticity and tensile strength. The molecular mobility within the silk's polymer structure on the nanometre length scale importantly contributes to these macroscopic properties. We have therefore investigated the ensemble-averaged single-particle self-dynamics of the prevailing hydrogen atoms in humid spider dragline silk fibres on picosecond time scales <i>in situ</i> as a function of an externally applied tensile strain. We find that the molecular diffusion in the amorphous fraction of the oriented fibres can be described by a generalized fractional diffusion coefficient <i>K<sub>α</sub></i> that is independent of the observation length scale in the probed range from approximately 0.3–3.5 nm. <i>K<sub>α</sub></i> increases towards a diffusion coefficient of the classical Fickian type with increasing tensile strain consistent with an increasing loss of memory or entropy in the polymer matrix.