BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Noy Cohen (Technion\, Haifa) DTSTART:20250408T134000Z DTEND:20250408T151000Z DTSTAMP:20260405T175005Z UID:NSCM/174 DESCRIPTION:Title: F rom micro to macro: Unraveling the origin of the counterintuitive response in spider silk fibers\nby Noy Cohen (Technion\, Haifa) as part of Ne čas Seminar on Continuum Mechanics\n\nLecture held in Faculty of Civil En gineering\, CTU\, Thákurova 7\, Praha 6\, Room B-168 EXCEPTIONALLY.\n\nA bstract\nSpider silk is an extraordinary protein material characterized by high strength and toughness. Upon exposure to high humidity\, silk fibers experience a reduction in stiffness of several orders of magnitude\, supe rcontraction (i.e.\, a shortening of up to ~60% in length)\, and twist. Th ese counterintuitive responses originate from a unique polymeric structure made of crystalline domains that are embedded in a highly aligned amorpho us matrix. Broadly\, high humidity leads to water uptake by the silk\, whi ch in turn motivates the dissociation of intermolecular hydrogen cross-lin king bonds. \nIn this talk\, I will present energetically motivated models based on tools from statistical mechanics that shed light on the relation s between the microstructure and the macroscopic behavior and capture the overall response of silk fibers. The models are validated through a compar ison to experimental findings. The insights from these models provide a me thod to characterize the microstructural evolution of hydrogen-bond domina ted networks and pave the way to the design of novel biomimetic fibers wit h non-trivial properties. \n\n1) R. Olive and N. Cohen\, “Deformation an d failure mechanisms in spider silk fibers”\, Journal of the Mechanics a nd Physics of Solids\, 182:105480\, 2024.\n\n2) N. Cohen\, “The underlyi ng mechanisms behind the hydration-induced and mechanical response of spid er silk”\, Journal of the Mechanics and Physics of Solids\, 172:105141\, 2023.\n\n3) N. Cohen and C.D. Eisenbach\, “Humidity-Driven Supercontrac tion and Twist in Spider Silk”\, Physical Review Letters\, 128:098101\, 2022.\n\n4) N. Cohen\, M. Levin\, and C.D. Eisenbach\, “On the origin of supercontraction in spider silk”\, Biomacromolecules\, 22:993-1000\, 20 21.\n\nPlease note the time and location change for this talk !!!\n LOCATION:https://researchseminars.org/talk/NSCM/174/ END:VEVENT END:VCALENDAR