Structure and Molecular Dynamics of Semicrystalline Polymers as Studied by Solid-state NMR

Abstract

Chain-level structure of semicrystalline polymers in melt- and solution-grown crystals has been debated over the past several decades. Recently, 13C–13C double quantum (DQ) NMR spectroscopy and spin-dynamics simulation have been applied to trace chain trajectory and packing structure of 13C labeled polymers in melt- and solution-grown crystals. We highlight recent NMR studies for (i) packing structure, (ii) chain trajectory, (iii) conformation of the folded chains, (iv) nucleation mechanisms in the early stage of crystallization, and (v) deformation mechanism at the molecular scale of semicrystalline polymers.

Enzyme-Responsive Modular Peptides Enhance Tumor Penetration of Quantum Dots via Charge Reversal Strategy

“…Herein, the obtained STD spectrum here could provide signals of ligands binding to QD suspended in aqueous solution. , The 1 H NMR spectrum of GG was shown in Figure c with the signal assignments assisted with the 1 H– 1 H homonuclear correlation spectrum (COSY, Figure S13). Figure d and Figure e show the STD spectra of GG-QD and peptide GG alone, respectively.…”

“…When bulk water is selectively irradiated, the saturation of water protons will transfer to the ligands bounded to nanoparticles via spin diffusion, while the saturation transfer will not occur for the free ligands. As a result, the difference spectrum ( S off – S on ) will show the signal of the ligand interacting with the nanoparticles. , …”

Using Abundant 1H Polarization to Enhance the Sensitivity of Solid-State NMR Spectroscopy

“…It should be noted that the recent advancements in ultrahigh magnetic field (above 1 GHz) and MAS probe technology (above 100 kHz spinning) have rendered proton-detected solid-state NMR methods the choice for structural analysis. By utilizing 2D 1 H-detected HETCOR experiments at 100 kHz MAS and 1.2 GHz (i.e., 28.2 T) magnetic field, Wiegand et al were able to capture the signals of an isolated trapped water molecule in a calix [4]arene lanthanide complex. 134 Brown et al further demonstrated the 1 H spectral resolution enhancement of 1 GHz compared to 600 MHz magnetic field, enabling insights into the specific hydrogen bonding interactions driving the crystal packing of Lorlatinib, an oral active pharmaceutical ingredient for treating lung cancer.…”

Elucidations of Structure and Molecular Dynamics of Complex Polymers by State-of-the-Art Solid-State NMR Spectroscopy

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