DWI - Leibniz-Institute for Interactive Materials, Forckenbeckstr 50, 52056, Aachen, Germany.
Institute for Applied Polymer Chemistry, University of Applied Sciences Aachen, Heinrich-Mussmann-Str. 1, 52428, Jülich, Germany.
Adv Mater. 2018 Aug;30(32):e1802477. doi: 10.1002/adma.201802477. Epub 2018 Jun 26.
Synthetic mimics of natural high-performance structural materials have shown great and partly unforeseen opportunities for the design of multifunctional materials. For nacre-mimetic nanocomposites, it has remained extraordinarily challenging to make ductile materials with high stretchability at high fractions of reinforcements, which is however of crucial importance for flexible barrier materials. Here, highly ductile and tough nacre-mimetic nanocomposites are presented, by implementing weak, but many hydrogen bonds in a ternary nacre-mimetic system consisting of two polymers (poly(vinyl amine) and poly(vinyl alcohol)) and natural nanoclay (montmorillonite) to provide efficient energy dissipation and slippage at high nanoclay content (50 wt%). Tailored interactions enable exceptional combinations of ductility (close to 50% strain) and toughness (up to 27.5 MJ m ). Extensive stress whitening, a clear sign of high internal dynamics at high internal cohesion, can be observed during mechanical deformation, and the materials can be folded like paper into origami planes without fracture. Overall, the new levels of ductility and toughness are unprecedented in highly reinforced bioinspired nanocomposites and are of critical importance to future applications, e.g., as barrier materials needed for encapsulation and as a printing substrate for flexible organic electronics.
仿生高性能结构材料的合成模拟为多功能材料的设计带来了巨大的、部分意料之外的机遇。对于珍珠层仿生纳米复合材料，在高增强分数下制备具有高拉伸性的韧性材料仍然极具挑战性，而这对于柔性阻隔材料至关重要。本研究通过在由两种聚合物（聚乙烯胺和聚乙烯醇）和天然纳米粘土（蒙脱土）组成的三元珍珠层仿生体系中引入较弱但数量众多的氢键，实现了高韧性和高韧性的珍珠层仿生纳米复合材料，为高纳米粘土含量（50wt%）下的高效能量耗散和滑动提供了条件。通过精心设计的相互作用，使材料在具有高内聚强度的情况下实现了优异的延展性（接近 50%的应变）和韧性（高达 27.5MJ m ）的结合。在机械变形过程中，可以观察到广泛的应力发白，这是高内部分子动力学的明显标志，并且这些材料可以像折纸一样折叠成折纸平面而不会断裂。总的来说，这种高韧性和高韧性在高增强仿生纳米复合材料中是前所未有的，对未来的应用具有重要意义，例如作为封装所需的阻隔材料和作为柔性有机电子的打印基板。
