Molecular Dynamics of Polycarbonate Chains at the Interface ofPolycarbonate/Polystyrene Heterogeneous Blends

摘要

Having generated and identified a (13)C-NMR signal arising exclusively from PCchains the PC/PS interface, we can now perform NMR relaxation experiments to characterize the microscopic dynamics of these chains. A difference pulse sequence is used which includes a period for carbon dephasing under the influence of dipolar coupling to protons isolated from one another by multiple-pulse H-H decoupling. Thus, the full experiment involves monitoring the dephasing of Dynamic Nuclear Polarization (DNP)-enhanced (13)C NMR magnetization of interface PC chains in a thin-film PC/PS blend by dipolar rotational spin echo (DRSE) 13 C NMR. The results of DRSE experiments have been well established for the characterization of the molecular chain dynamics of synthetic polymers and proteins.