Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
Division of Forest and Biomaterials Science, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.
Angew Chem Int Ed Engl. 2021 Nov 8;60(46):24630-24636. doi: 10.1002/anie.202110032. Epub 2021 Oct 7.
Crystallites form a grain boundary or the inter-crystallite interface. A grain boundary is a structural defect that hinders the efficient directional transfer of mechanical stress or thermal phonons in crystal aggregates. We observed that grain boundaries within an aggregate of crystalline cellulose nanofibers (CNFs) were crystallized by enhancing their inter-crystallite interactions; multiple crystallites were coupled into single fusion crystals, without passing through a melting or dissolving state. Accordingly, the lowered crystallinity of CNFs, which has been considered irreversible, was recovered, and the thermal energy transfer in the aggregate was significantly improved. Other nanofibrous crystallites of chitin also showed a similar fusion phenomenon by enhancing the inter-crystallite interactions. Such crystallite fusion may naturally occur in biological structures with network skeletons of aggregated fibrillar crystallites having mechanical or thermal functions.
微晶形成晶界或晶间界面。晶界是一种结构缺陷，会阻碍晶体聚集体中机械应力或热声子的有效定向传递。我们观察到，通过增强结晶纤维素纳米纤维（CNF）聚集体中各晶间的相互作用，晶界发生结晶；多个微晶结合成单个熔融晶体，而无需经过熔融或溶解状态。因此，降低了的 CNF 结晶度（被认为是不可逆的）得到恢复，并且聚集体中的热能传递得到显著改善。壳聚糖的其他纳米纤维状微晶通过增强晶间相互作用也表现出类似的熔融现象。在具有机械或热功能的纤维状结晶聚集体网络骨架的生物结构中，这种微晶融合可能会自然发生。
