冰模板技术仿生构筑层状高分子纳米复合材料的研究进展

Recent Advances in the Nacre-inspired Layered Polymer Nanocomposites by Ice Templating Technique

冰模板技术也称为定向冷冻铸造技术,是指将基本组装单元、溶剂和添加剂均匀分散或溶解,利用溶剂的“液-固-气”的相转变构筑层状多孔材料的新颖技术.受贝壳珍珠层“砖-泥”层状结构的启发,通过对层状骨架密实化处理,可构筑仿贝壳珍珠层复合材料.对冰模板技术构筑的层状高分子纳米复合材料的前沿进展进行了系统的归纳和总结.首先,根据冰模板技术构筑不同厚度“砖”致密化策略进行分类,分为骨架填充高分子、骨架热压处理和骨架矿化三种策略,通过实例解读每种策略构筑的典型层状高分子纳米复合材料及其性能.随后,对冰模板技术构筑的层状高分子纳米复合材料的设计与功能特性进行了分析和讨论,如调控微观结构、引入功能基元材料和提高界面相互作用等,不仅改善了层状高分子纳米复合材料的力学性能,同时赋予了纳米复合材料电磁屏蔽、导热和结构完整自监测等功能.最后,对冰模板技术仿生构筑的层状高分子纳米复合材料的结构设计、性能优化和应用拓展等未来的发展方向及存在的挑战进行了展望.

Ice templating,known as directional freeze casting,is a novel technique for constructing laminar porous materials by homogeneously dispersing or dissolving the building blocks,solvents and additives and using the“liquid-solid-gas”phase transition of the solvent.Inspired by the“brick-mortar”layered structure,the lamellar scaffold prepared from ice templating can be densified to construct nacre-like composite.This work presents a timely and systematic investigation and summary of frontier progresses of layered polymer nanocomposites constructed by the ice templating technique.Firstly,the densification strategies are classified according the different thickness of“brick”into three strategies:lamellar scaffold-filled polymer,hot-pressing treatment and mineralization.And typical layered polymer nanocomposites constructed by each strategy and their properties are also presented with classical examples.Subsequently,the design and functional applications of layered polymer nanocomposites are analyzed and discussed,such as the modulation of microstructures,introduction of functional building blocks,and enhancement of interfacial interactions,which not only improve the mechanical properties of layered polymer nanocomposites,but also endow them with functional applications,such as electromagnetic shielding,thermal conductivity and self-monitoring of structural integrity.Finally,we provide an outlook on the future directions and challenges of the structural design,performance optimization and application expansion of nacre-inspired layered polymer nanocomposites constructed by the ice templating technique.