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Silk Polymer Models for Structure-Function Relationships David Kaplan, Tufts University, DMR 0402849.
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Silk Polymer Models for Structure-Function RelationshipsDavid Kaplan, Tufts University, DMR 0402849 Background– Silk, a natural protein biopolymer produced by silkworms and spiders, is formed into fibers with remarkable mechanical properties. Like synthetic polymers, silk can crystallize (through beta sheet formation). Crystallization spontaneously occurs during water removal in naturally occurring silks. Water removal directly impacts the mechanical properties and the ability to form new high performance materials from these proteins. Objective – To use calorimetry (heat flow) and thermo- gravimetry (weight loss) to determine the total water content in silk. This will allow us to better understand both the natural silk fiber formation process as well as to elucidate new approaches outside the organisms in order to form new materials from this protein. Figure – Top: Depicts the weight lost by silk films during heating at different rates. The weight decreases, from room temperature to 165C, due to water removal, followed by degradation at higher temperatures. Bottom: Depicts heat flow vs. temperature. Cycles 1-6: By successively heating to higher temperatures water is steadily removed from silk. The glass transition process of dry silk can be seen at 178C after all water has been removed. Data from: Hu, X.; Kaplan, D.; Cebe, P. Thermichimica Acta, in press 7/2007.
b a c e Silk Polymer Models for Structure-Function RelationshipsDavid Kaplan, Tufts University,DMR 0402849 Educational AspectsProfs. Kaplan and Cebe provide research opportunities and mentoring for undergraduate and graduate students. a. Graduate student Xiao Hu’s poster on crystallinity determination in silk was one of those nominated for best poster at the Fall 2006 Materials Research Society; b. Undergraduate members of the Tufts Society of Physics Students enjoy pizza after Prof. Cebe (second from right) presented a seminar on topics in biophysics; c. Prof. G. Georgiev (left), Assumption College, with Tufts graduate students at the 2007 American Physical SocietyMarch Meetingposter session. d. Prof. Jon Garlick of d Tufts Medical School shows artificial skin tissue to undergraduate interns who visited his lab on Career Day.