Schäfer, Timmy, Steffen Vowinkel, Hergen Breitzke, Markus Gallei, and Torsten Gutmann. “Selective DNP Signal Amplification To Probe Structures of Core–Shell Polymer Hybrid Nanoparticles.” The Journal of Physical Chemistry C 123, no. 1 (January 10, 2019): 644–52.
An efficient approach for the characterization of core-shell polymer hybrid nanoparticles is presented. Selective signal amplification by dynamic nuclear polarization (DNP) is employed to shed more light on the molecular structure of surface sites and of the shell of the particles. DNP enhanced 29Si solid-state NMR is used to clearly prove the core-shell structure of the nanoparticles as well as the success of their functionalization with low amounts of trimethylsiloxy groups. By combination of DNP enhanced 1H-29Si and 1H-13C cross-polarization magic-angle-spinning (CP MAS) experiments, differently substituted alkoxysilane moieties, namely methacryloxypropyltriethoxysilane (MPSEt), 3- methacryloxypropyltriisopropoxysilane (MPSIsoprop) and 3-methacryloxypropyltris (methoxyethoxy)silane (MPSMeEt) are investigated, revealing various crosslinking capabilities of the particle shell. This knowledge about efficiency of surface functionalization and cross-linking sites strongly influences the application and properties of the core-shell polymer hybrid particles for instance as materials for photonic crystals, particle film formation and coatings. This is of high importance for the design of tailor-made core-shell particle architectures.