DWI-Leibniz Institute for Interactive Materials , Forckenbeckstr. 50, 52074 Aachen, Germany.
Preparative Macromolecular Chemistry, Institut für Technische Chemie und Polymerchemie, Karlsruhe Institute of Technology (KIT) , Engesserstr. 18, 76128 Karlsruhe, Germany.
Nano Lett. 2016 Aug 10;16(8):5176-82. doi: 10.1021/acs.nanolett.6b02127. Epub 2016 Jul 27.
Nature provides design paradigms for adaptive, self-healing, and synergistic high-performance structural materials. Nacre's brick-and-mortar architecture is renowned for combining stiffness, toughness, strength, and lightweightness. Although elaborate approaches exist to mimic its static structure and performance, and to incorporate functionalities for the engineering world, there is a profound gap in addressing adaptable mechanical properties, particularly using remote, quick, and spatiotemporal triggers. Here, we demonstrate a generic approach to control the mechanical properties of nacre-inspired nanocomposites by designing a photothermal energy cascade using colloidal graphene as light-harvesting unit and coupling it to molecularly designed, thermoreversible, supramolecular bonds in the nanoconfined soft phase of polymer/nanoclay nacre-mimetics. The light intensity leads to adaptive steady-states balancing energy uptake and dissipation. It programs the mechanical properties and switches the materials from high stiffness/strength to higher toughness within seconds under spatiotemporal control. We envisage possibilities beyond mechanical materials, for example, light-controlled (re)shaping or actuation in highly reinforced nanocomposites.
大自然为自适应、自修复和协同的高性能结构材料提供了设计范例。珍珠母的砖泥结构以结合刚度、韧性、强度和轻量化而闻名。尽管已经存在一些精细的方法来模拟其静态结构和性能，并为工程世界融入功能，但在解决自适应机械性能方面仍存在巨大差距，特别是在使用远程、快速和时空触发方面。在这里，我们通过设计使用胶体石墨烯作为光收集单元的光热能量级联，并将其与聚合物/纳米粘土珍珠母模拟物的纳米受限软相中分子设计的、热可逆的超分子键耦合，展示了一种控制基于珍珠母的纳米复合材料机械性能的通用方法。光强度导致自适应稳态平衡能量吸收和耗散。它在几秒钟内根据时空控制编程机械性能，并将材料从高刚度/强度切换到更高的韧性。我们设想了超越机械材料的可能性，例如在高度增强的纳米复合材料中进行光控（再）成型或致动。
