SKM 2021 – wissenschaftliches Programm
CPP 4.1: Hauptvortrag
Dienstag, 28. September 2021, 10:00–10:30, H3
Adaptable amphiphilic co-networks: structure and properties in relation with multi-quantum NMR — •Michael Lang1, Reinhard Scholz1, Lucas Löser2, Carolin Bunk1, Frank Böhme1, and Kay Saalwächter2 — 1Leibniz-Institut für Polymerforschung, Hohe Straße 6, 01069 Dresden, Germany — 2Martin-Luther-Universität Halle-Wittenberg, Institut für Physics - NMR Group, Betty-Heimann-Str. 7, 06120 Halle, Germany
Amphiphilic co-networks made by the hetero-complementary coupling of four arm star polymers are an interesting model system to understand the physics of adaptive co-networks and currently the focus of the DFG research unit FOR2811 in which we participate. We analyze these model networks in different states (preparation in co-solvent, swollen state, and "switched" states where one type of polymer is swollen and the other collapsed) with large scale Monte-Carlo simulations and experiments. We discuss the degree of swelling, the scattering function, chain extensions, etc. of these model systems briefly. A particular focus is put on data and models regarding proton multiple-quantum NMR. After a brief tutorial on what can be analyzed with this method, we sketch analytical models for NMR order parameters in a particular state and compare with the availabe simulation or experimental data in these states. This analysis provides useful information on the time average local properties of individual network strands including the strain distribution of network strands. Such information is hardly accessible with alternative methods and allows even for the analysis of cyclic network defects under appropriate conditions.