In the current quest for the design of advanced complex materials, the functionalization of biological materials having hierarchical structures has been of high interest. In the case of lignocellulosic materials, various modification techniques have allowed one to obtain materials with outstanding properties. However, the control over the spatial distribution of the modification inside the wood scaffold, which is an important parameter to obtain the desired properties, has yet to be understood. In this study, the use of solvents with different wood-swelling capabilities is proposed to control the spatial polymer-modification distribution inside the hierarchical wood structure. Wood cubes were functionalized via SI-AGET-ATRP using solvents with different wood-swelling capabilities. Spectroscopic (Raman and FTIR) and electron microscopy techniques showed that a good wood-swelling solvent as reaction media can transport the polymerization initiator molecule into the cell wall, allowing it to react with all the available -OH groups in the wood structure. Conversely, the use of a bad wood-swelling solvent limits the reaction to the available -OH groups at the lumen/cell wall interface. The subsequently added polymers grow from the available initiator sites and therefore show similar spatial distribution. This diffusion limitation is visible not only at the microscopic level (cellular structure) but also at the macroscopic level (over the length of the sample).

中文翻译：

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SI-AGET-ATRP接枝聚合物在木质纤维素材料中的溶剂控制空间分布。

在当前对高级复杂材料的设计的追求中，具有分层结构的生物材料的功能化引起了人们的极大兴趣。对于木质纤维素材料，各种改性技术已使人们能够获得具有优异性能的材料。然而，对于木质支架内部的变体的空间分布的控制，这是获得所需特性的重要参数，尚未被理解。在这项研究中，提出了使用具有不同木材溶胀能力的溶剂来控制分层木材结构内部的空间聚合物改性分布。使用具有不同木材溶胀能力的溶剂通过SI-AGET-ATRP对木材进行功能化。光谱（拉曼光谱和FTIR）和电子显微镜技术表明，良好的木材膨胀溶剂作为反应介质可以将聚合引发剂分子转运到细胞壁中，使其与木材结构中所有可用的-OH基团发生反应。相反，使用不良的木材溶胀溶剂将反应限制为在管腔/细胞壁界面处可用的-OH基团。随后添加的聚合物从可用的引发剂位点生长，因此显示出相似的空间分布。这种扩散限制不仅在微观水平（细胞结构）上可见，而且在宏观水平（在样品的整个长度上）上也是可见的。使其与木结构中所有可用的-OH基团反应。相反，使用不良的木材溶胀溶剂将反应限制为在管腔/细胞壁界面处可用的-OH基团。随后添加的聚合物从可用的引发剂位点生长，因此显示出相似的空间分布。这种扩散限制不仅在微观水平（细胞结构）上可见，而且在宏观水平（在样品的整个长度上）上也是可见的。使其与木结构中所有可用的-OH基团反应。相反，使用不良的木材溶胀溶剂将反应限制为在管腔/细胞壁界面处可用的-OH基团。随后添加的聚合物从可用的引发剂位点生长，因此显示出相似的空间分布。这种扩散限制不仅在微观水平（细胞结构）上可见，而且在宏观水平（在样品的整个长度上）上也是可见的。