基于纳米纤维素设计合成高韧性和高拉伸强度的取向复合气凝胶

The practical applications of aerogels are limited by their low compressive strength and tensile strength. In recent years, a few of methods have been developed to improve the compressive strength of aerogels. However, reports on how to improve their tensile brittleness and tensile strength are very rare. In this project, we speculated that the tensile strength of aerogels may be improved by using the oriented nanocellulose. Nanocellulose exhibits the advantages of low density, high strength, high elasticity modulus and large surface area. For this view, we attempt to prepare the oriented nanocellulose-based aerogels with high toughness and tensile strength. The interfacial interactions between composite network and nanocellulose would be enhanced by introducing a complex network onto the hydroxyl groups of nanocellulose, thus improving the tensile strength and toughness of aerogels. The tensile mechanism of aerogels will be investigated by controlled experiments and simulation calculations. This project may provide new ideas for the design and synthesis of aerogel materials, and will be valuable to solve the basic problems in this field, such as low mechanical properties and weak tensile strength. The result will be of great significance for the commercialization of aerogel materials and can provide theoretical basis and experimental parameters for the development and applications of aerogels.

气凝胶的抗压缩和抗拉伸强度是决定其实际应用的关键问题。近年来，关于提高气凝胶抗压缩强度的报道较多，然而，关于提高气凝胶的抗拉伸强度及韧性的报道较少。本项目推测：气凝胶网络结构的定向排列有望提高其抗拉伸强度的能力。基于纳米纤维素密度低、强度高、弹性模量和比表面积大等优点，本项目拟以纳米纤维素为原料，制备得到一种高拉伸强度、高韧性的取向复合气凝胶，即：（1）通过纳米纤维素的定向排列,在其表面的羟基上引入复合网络，将取向纳米纤维素锚定，从而增强复合网络与纳米纤维素的界面作用力，提高气凝胶的拉伸强度和韧性，（2）通过对照实验和模拟计算，探讨气凝胶的抗拉伸机制。本项目能够为气凝胶材料的设计合成提供新的思路，有望解决气凝胶力学性能差、抗拉伸强度弱等重大科学问题，从而为气凝胶的开发与应用提供理论依据和实验参数，对气凝胶材料的商业化应用具有重要意义。

如何提高气凝胶的抗拉伸强度及韧性，是气凝胶材料实际应用中非常重要但是却容易被忽视的关键问题。本项目通过取向和交联反应制备得到了具有高拉伸强度、高韧性等特征的气凝胶、水凝胶材料，研究了凝胶材料抗拉伸强度和结构之间的关系，并测定了材料的导电性能，在凝胶材料力学性能差、抗拉伸强度弱等问题方面取得了一定进展，为新型凝胶材料的设计合成提供实验参数和理论依据。同时，本项目基于自组装纳米材料的交联反应及其在固体界面的原位自组装，根据凝胶纳米网络结构的导电性及电化学特征，构建了一系列传感器件用于重要生物分子的检测，为高灵敏生物传感器的设计和研制提供了新的思路。