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Internal Structure of Methylcellulose Fibrils
Macromolecules ( IF 5.1 ) Pub Date : 2020-01-02 , DOI: 10.1021/acs.macromol.9b01773 Peter W. Schmidt , Svetlana Morozova , S. Piril Ertem , McKenzie L. Coughlin , Irina Davidovich 1 , Yeshayahu Talmon 1 , Theresa M. Reineke , Frank S. Bates , Timothy P. Lodge
Macromolecules ( IF 5.1 ) Pub Date : 2020-01-02 , DOI: 10.1021/acs.macromol.9b01773 Peter W. Schmidt , Svetlana Morozova , S. Piril Ertem , McKenzie L. Coughlin , Irina Davidovich 1 , Yeshayahu Talmon 1 , Theresa M. Reineke , Frank S. Bates , Timothy P. Lodge
Affiliation
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Methylcellulose (MC) is a water-soluble cellulose derivative with a wide range of commercial applications. Upon heating, MC solutions reversibly form ∼15–20 nm diameter fibrils, which percolate into a fibrillar network, resulting in macroscopic gelation. Using mid-angle X-ray scattering (MAXS) and wide-angle X-ray scattering (WAXS), we have analyzed MC chain organization within fibrils aligned in dried films that have been stretched by over 300%. MAXS and WAXS show distinct anisotropic scattering features, which we interpret as reflecting crystalline domains within the fibrils. The scattering peaks are consistent with a body-centered monoclinic unit cell, with similar dimensions as other cellulosic crystals, a = 11.4 Å, b = 8.9 Å, and c = 10.2 Å, and γ in the range of 90–100°, with MC chains oriented along the long axis of the fibril. Phase-plate cryogenic transmission electron microscopy images of MC fibrils contribute to a more comprehensive picture. Along the long axis of MC fibrils, there is evidence of dense twisted domains, which are interpreted as regions containing semicrystalline MC, interspersed with looser, less organized amorphous domains. Together, these two techniques provide the most complete interpretation of MC subfibril structure currently available.
中文翻译：
甲基纤维素原纤维的内部结构
甲基纤维素（MC）是一种水溶性纤维素衍生物，具有广泛的商业应用。加热后，MC溶液可逆地形成直径约15-20 nm的原纤维，这些原纤维渗透到原纤维网络中，导致宏观凝胶化。使用中角X射线散射（MAXS）和广角X射线散射（WAXS），我们分析了在干燥薄膜中对齐的原纤维中的MC链组织，该干燥薄膜拉伸了300％以上。MAXS和WAXS显示出独特的各向异性散射特征，我们将其解释为反映了原纤维内的晶畴。散射峰与以人体为中心的单斜晶胞一致，其尺寸与其他纤维素晶体相似，a = 11.4Å，b = 8.9Å，c= 10.2Å，且γ在90–100°范围内，MC链沿原纤维的长轴定向。MC原纤维的相板低温透射电子显微镜图像有助于获得更全面的图像。沿着MC原纤维的长轴，有密集的扭曲结构域的证据，该结构域被解释为包含半结晶MC的区域，其间散布着较松散的，组织较少的无定形结构域。这两种技术结合在一起，可以对目前可用的MC亚原纤维结构提供最完整的解释。
更新日期：2020-01-04
中文翻译：
甲基纤维素原纤维的内部结构
甲基纤维素（MC）是一种水溶性纤维素衍生物，具有广泛的商业应用。加热后，MC溶液可逆地形成直径约15-20 nm的原纤维，这些原纤维渗透到原纤维网络中，导致宏观凝胶化。使用中角X射线散射（MAXS）和广角X射线散射（WAXS），我们分析了在干燥薄膜中对齐的原纤维中的MC链组织，该干燥薄膜拉伸了300％以上。MAXS和WAXS显示出独特的各向异性散射特征，我们将其解释为反映了原纤维内的晶畴。散射峰与以人体为中心的单斜晶胞一致，其尺寸与其他纤维素晶体相似，a = 11.4Å，b = 8.9Å，c= 10.2Å，且γ在90–100°范围内，MC链沿原纤维的长轴定向。MC原纤维的相板低温透射电子显微镜图像有助于获得更全面的图像。沿着MC原纤维的长轴，有密集的扭曲结构域的证据，该结构域被解释为包含半结晶MC的区域，其间散布着较松散的，组织较少的无定形结构域。这两种技术结合在一起，可以对目前可用的MC亚原纤维结构提供最完整的解释。
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