The integration of metal–organic frameworks (MOFs) into renewable matrices, including those derived from cellulose, to create cellulose/MOF hybrids has attracted significant interest due to the synergistic combination of cellulosic biopolymer properties and MOFs' multifunctional features. The interfacial interactions between cellulose and MOF not only ensure stable bonding, but ultimately also determine the bulk physical properties of the macroscopic composites. However, the mechanistic understanding of the in situ assembly between the two materials remains unclear. In this study, we employ a combination study of synthesis, experimental characterization, and molecular dynamics simulations to explore the early-stage assembly of a cellulose/MOF hybrid. Our results revealed that the growth of MOF clusters on the 2,2,6,6-tetramethyl-1-piperidinyloxy oxidized cellulose nanofibrils (TOCNF) follows an inhomogeneous sequential transformation pathway. The carboxylates of TOCNF form coordination-like bonds with the metal ions, while the hydroxyl groups of TOCNF form hydrogen bonds with MOF ligands. These interactions provide the initial nucleation sites that mediate the growth of MOF clusters and also guide the assembly of larger MOF clusters onto the TOCNF substrate. The fundamental insights into the in situ assembly of MOF nanoparticles on cellulosic substrates are essential for the rational design of high-performance materials with tailored morphology and optimized properties.

中文翻译：

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纤维素纳米原纤维上金属-有机框架原位早期组装的分子见解


由于纤维素生物聚合物特性和 MOF 的多功能特性的协同结合，将金属有机框架 （MOF） 整合到可再生基质（包括来自纤维素的基质）中以产生纤维素/MOF 杂化物，引起了人们的极大兴趣。纤维素和 MOF 之间的界面相互作用不仅确保了稳定的粘合，而且最终决定了宏观复合材料的体物理性能。然而，对两种材料之间原位组装的机理理解仍不清楚。在本研究中，我们采用合成、实验表征和分子动力学模拟的组合研究来探索纤维素/MOF 杂交体的早期组装。我们的结果表明，2,2,6,6-四甲基-1-哌啶氧基氧化纤维素纳米纤维 （TOCNF） 上 MOF 簇的生长遵循不均匀的连续转化途径。TOCNF 的羧酸盐与金属离子形成配位样键，而 TOCNF 的羟基与 MOF 配体形成氢键。这些相互作用提供了介导 MOF 簇生长的初始成核位点，并指导较大的 MOF 簇组装到 TOCNF 底物上。对 MOF 纳米颗粒在纤维素衬底上的原位组装的基本见解对于合理设计具有定制形态和优化性能的高性能材料至关重要。