有序和无序纤维素纳米晶体薄膜的固态钠 NMR 光谱研究。
Solid-state Na NMR spectroscopy studies of ordered and disordered cellulose nanocrystal films.
机构信息
Department of Chemistry, Graduate School of Natural Science & Technology, Kanazawa University, Kakuma-machi, Kanazawa, 920-1192, Japan; Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada; Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada.
出版信息
Solid State Nucl Magn Reson. 2019 Feb;97:31-39. doi: 10.1016/j.ssnmr.2018.12.001. Epub 2018 Dec 14.
Cellulose nanocrystal films with either disordered or chiral nematic structures of varying helical pitch were investigated using Na solid-state nuclear magnetic resonance (NMR) spectroscopy. Spin lattice relaxation of H correlated with Na analyzed by indirect observation using polarization transfer from H nuclei to Na nuclei showed that the Na cations are well hydrated in the cellulose nanocrystal films. Linewidth analysis in solid-state Na NMR showed that the Na cations move in confined spaces, and that the Na cations in the film having disordered structure are more dynamic than in the films having ordered structure. From lineshape analysis of the Na 2D nutation NMR spectra, we can distinguish the Na environments within the ordered and disordered films, and find trends in anisotropic interaction parameters between ordered samples with different pitches. These are the first detailed Na NMR spectroscopic studies of CNC-Na films, and they show that this technique may be a powerful probe for characterizing the extent of order in nanocellulose samples.
采用 Na 固态核磁共振（NMR）光谱法研究了具有不同螺旋间距的无序向列相或手性向列相的纤维素纳米晶薄膜。通过间接观察 H 核到 Na 核的极化转移分析 H 与 Na 的自旋晶格弛豫表明，Na 阳离子在纤维素纳米晶薄膜中很好地水合。固态 Na NMR 的线宽分析表明，Na 阳离子在受限空间中移动，无序结构薄膜中的 Na 阳离子比有序结构薄膜中的 Na 阳离子更具动态性。通过 Na 2D 章动 NMR 谱的线形分析，我们可以区分有序和无序薄膜中的 Na 环境，并发现不同螺距有序样品之间各向异性相互作用参数的趋势。这是对 CNC-Na 薄膜的首次详细的 Na NMR 光谱研究，表明该技术可能是表征纳米纤维素样品有序程度的有力探针。
Zotero 插件