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

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.