High-performance bulk materials of self-organized cellulose nanofibrils

纤维素是在植物细胞壁中以晶体微原纤维的形式产生的，具有优异的材料性能。这些微纤维作为纳米材料的结构成分最近引起了人们的极大兴趣。我们首次发现，通过在纤维素微原纤维上应用拓扑表面羧化反应，纤维素可以作为单个微原纤维完全分散在水中。分散的微纤维在水中自发排列。自排列微纤维的集成控制，即仔细调整pH值和微纤维分散体中溶剂的蒸发，产生了各种具有优异性能的人造大块材料。例如前所未有的高硬度水凝胶，其含水量高达99.9%，以及具有机械韧性和高绝热性的透明气凝胶。

Cellulose is produced in plant cell walls as crystalline microfibrils with excellent material properties. These microfibrils have recently been attracting much interest as structural components in nanomaterials. We have found for the first time that cellulose can be fully dispersed in water as individual microfibrils via the application of a topological surface carboxylation reaction on cellulose microfibrils. The dispersed microfibrils spontaneously align in water. The integration controls of the self-aligned microfibrils, i.e., careful adjustment of the pH and evaporation of the solvent in the microfibril dispersions, produces a wide range of artificial bulk materials with outstanding properties. Examples include unprecedentedly stiff hydrogels that are free-standing with a water content of 99.9%, and transparent aerogels with mechanical toughness and high heat-insulation.