School of Biotechnology, Royal Institute of Technology, Alba Nova University Centre , SE-106 91 Stockholm, Sweden.
Wallenberg Wood Science Center, Royal Institute of Technology , SE-100 44 Stockholm, Sweden.
ACS Appl Mater Interfaces. 2017 Jun 14;9(23):20169-20178. doi: 10.1021/acsami.7b02177. Epub 2017 May 31.
The interfacial adhesion design between "mortar" and "bricks" is essential for mechanical and barrier performance of nanocellulose-based nacre-mimetic nanocomposites, especially at high moisture conditions. To address this fundamental challenge, dopamine (DA) has been conjugated to cellulose nanofibrils (CNFs) and subsequently assembled with montmorillonite (MTM) to generate layered nanocomposite films inspired by the strong adhesion of mussel adhesive proteins to inorganic surfaces under water. The selective formation of catechol/metal ion chelation and hydrogen bonding at the interface between MTM platelets and CNFs bearing DA renders transparent films with strong mechanical properties, particularly at high humidity and in wet state. Increasing the amount of conjugated DA on CNFs results in nanocomposites with increased tensile strength and modulus, up to 57.4 MPa and 1.1 GPa, respectively, after the films are swollen in water. The nanocomposites also show excellent gas barrier properties at high relative humidity (95%), complementing the multifunctional property profile.
“灰浆”和“砖块”之间的界面黏合设计对于基于纳米纤维素的仿珍珠层纳米复合材料的机械性能和阻隔性能至关重要，尤其是在高湿度条件下。为了解决这一基本挑战，将多巴胺（DA）接枝到纤维素纳米纤维（CNF）上，然后与蒙脱石（MTM）组装，生成受贻贝黏附蛋白在水下与无机表面强黏附启发的层状纳米复合材料薄膜。MTM 薄片和带有 DA 的 CNF 之间界面处的儿茶酚/金属离子螯合和氢键的选择性形成赋予了透明薄膜强机械性能，特别是在高湿度和潮湿状态下。增加 CNF 上接枝 DA 的量可使纳米复合材料的拉伸强度和模量分别增加至 57.4 MPa 和 1.1 GPa，而薄膜在水中溶胀后。纳米复合材料在高相对湿度（95%）下也表现出优异的气体阻隔性能，补充了多功能性能特征。
