Solid-State NMR InvestigatIons of the Unusual Effects Resulting from the Nanoconfinement of Water within Amphiphilic Crosslinked Polymer Networks

摘要

Two types of solid-state ~(19)F NMR spectroscopy experiments are used to characterize phase-separated hyperbranched fluoropolymer-poly(ethylene glycol) (HBFP-PEG) crosslinked networks. Mobile (soft) domains are detected in the HBFP phase by a rotor-synchronized Hahn echo under magic-angle spinning conditions, and rigid (hard) domains by a solid echo with no magic-angle spinning. The mobility of chains is detected in the PEG phase by ~H→~(13)C cross-polarization transfers with ~1H spin-lock filters with and without magic-angle spinning. The interface between HBFP and PEG phases is detected by a third experiment, which utilized a ~(19)F→~1H-(spin diffusion)-~1H →~(13)C double transfer with ~(13)C solid-echo detection. The results of these experiments show that composition-dependent PEG inclusions in the HBFP glass rigidify on hydration, consistent with an increase in macroscopic tensile strength.