纤维素纳米纸的疏水改性及应用研究

纳米纤维素(NC)是自然界来源丰富的可再生天然高分子材料，不仅具备纤维素的基本性质，还拥有纳米材料的特殊性能.目前，以NC为基本单元成功制备了多种性能优异的结构和功能材料，其中由NC制备的柔性、透明纤维素纳米纸(CNP)材料因具有优异的力学性能、光学性能和热学性能，现已在各种多功能和高端应用上广泛使用.然而由于NC天然的亲水性，导致CNP材料在潮湿环境下的力学性能急剧下降，严重影响了CNP的应用性能.因此，改善CNP的亲水性，保持材料在潮湿环境下也具有增强的力学性能是纤维素应用不容忽视的问题.本文首先介绍了CNP的制备与性质，接着回顾了甲硅烷基化、乙酰化/酯化、聚合物接枝和物理吸附在CNP疏水改性上的研究进展，重点阐述了改性对CNP表面疏水性和应用性能的影响；最后介绍了CNP材料在太阳能电池、超级电容器和有机发光二极管上的应用.

Hydrophobic modification and application of cellulose nanopaper

Nanocellulose (NC) has generated a tremendous level of attention, for it combines the key properties of cellulose and the special properties characteristic of nanoscale materials. Currently, NC has been successfully used as the building blocks for designing a variety of structural and functional materials with excellent properties. Especially, flexible and transparent cellulose nanopaper (CNP) prepared by NC has been widely used in various multifunctional and advanced applications because of its excellent mechanical, optical, and thermal properties. However, due to the natural hydrophilicity of NC, the mechanical properties of CNP under humid conditions decrease sharply, which seriously affects the application properties of CNP. Consequently, maintaining the enhanced mechanical properties of CNP under humid conditions is an important problem for cellulose applications. Here, we present a comprehensive review of the current research activities of hydrophobic modification of CNP and the applications of CNP in flexible/wearable electronics. First, a brief introduction of the preparation and properties of CNP is given. Then a comprehensive review of the current research activities of hydrophobic modification of CNP by methylsilylation, acetylation/esterification, polymer grafting, and physical adsorption is presented, which focuses on the influence of modification on the hydrophobicity and the application properties of CNP. Finally, the applications of CNP materials in solar cells, supercapacitors, and organic light emitting diodes are introduced.