Synthesis and Bond-Dynamics of Pseudo-BlockCopolymers

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The current proposal deals with the generation of microphase separated pseudoblockcopolymers, focusing on their dynamic behavior in the solid state, with a long-term perspective on the generation of self-healing materials. In contrast to the normally used covalent bond in blockcopolymers between immiscible polymers, hydrogen bonding systems (exerting binding strength ranging from Kassn ~ 25 M-1 till ~100,000 M-1, thus displaying a kinetic spectrum of formation/reformation ranging from ~0.01 s-1 to ~100 s-1) will be used to act as attractive force between immiscible, telechelic polymers. Several polymers ((PIB/PNB; PIB/PDMS) (polymer-abbreviations: polyisobutylene (PIB); poly(norbornene) (PNB); poly(dimethylsiloxane) (PDMS)), which display different thermal transition-temperatures (Tg) and Flory-Huggins interaction parameters () in the molecular-weight-range from 5000 g mol-1 to ~25,000 g mol-1) will be investigated, in order to study the dynamics of the resulting material-system. Dynamic-mechanical measurements, small angle x-ray scattering (SAXS), in-situ-Rheo-SAXS and solid-state NMR-spectroscopy will be used to gain information on the mobility of individual polymer chains and the nature of the hydrogen-bonds acting as molecular “glue” between them.