Dresden 2020 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 24: Poster Session I

CPP 24.5: Poster

Monday, March 16, 2020, 17:30–19:30, P3

Structural properties and chain connectivity in squid-based biopolymer networks analysed by 1H time-domain NMR experiments — •Lucas Löser¹, Huihun Jung², Melik Demirel², and Kay Saalwächter¹ — ¹Inst. f. Physik - NMR, Martin-Luther-Universität Halle-Wittenberg, Halle — ²Dep. of eng. science and mechanics, Pennsylvania State University, Pennsylvania

A variety of structural and topological factors is known to strongly influence the mechanical properties of a polymer network. Here, we focus on a molecular-engineered biopolymer network consisting of random coils and nano-sized β-sheet crystals (acting as physical crosslinks) that was obtained by modifying and expressing repetitive elements in the genetic code of squid-ring teeth proteins. Usage of different solvents and different chain lengths of the expressed biopolymer yields the possibility of variations in crystallinity and the amount of topological defects. Using 1H time-domain NMR experiments, namely free induction decay (FID) analysis and a double-quantum (DQ) experiment, we investigate the crystalline and mobile fraction, as well as the different chain connectivities being present in the network. Additionally, we investigate the segmental mobility along the elastic chain and show that a mobility gradient exists, which is possibly induced by confinement of the elastic chains due to the β-sheet crystals. We show that we can correlate β-sheet content and the crystallinity measured by FID analysis, and additionally we discuss a previously published entropic-elasticity model [1] in the context of our DQ-NMR results.[1] A. Pena-Francesch et. al., ACS Biomater. Sci. Eng. 2018, 4, 3, 884-891