School of Engineering and Applied Sciences, Harvard University, USA.
Chem Soc Rev. 2013 Sep 7;42(17):7072-85. doi: 10.1039/c3cs60045a. Epub 2013 Apr 26.
A living organism is a bundle of dynamic, integrated adaptive processes: not only does it continuously respond to constant changes in temperature, sunlight, nutrients, and other features of its environment, but it does so by coordinating hierarchies of feedback among cells, tissues, organs, and networks all continuously adapting to each other. At the root of it all is one of the most fundamental adaptive processes: the constant tug of war between chemistry and mechanics that interweaves chemical signals with endless reconfigurations of macromolecules, fibers, meshworks, and membranes. In this tutorial we explore how such chemomechanical feedback - as an inherently dynamic, iterative process connecting size and time scales - can and has been similarly evoked in synthetic materials to produce a fascinating diversity of complex multiscale responsive behaviors. We discuss how chemical kinetics and architecture can be designed to generate stimulus-induced 3D spatiotemporal waves and topographic patterns within a single bulk material, and how feedback between interior dynamics and surface-wide instabilities can further generate higher order buckling and wrinkling patterns. Building on these phenomena, we show how yet higher levels of feedback and spatiotemporal complexity can be programmed into hybrid materials, and how these mechanisms allow hybrid materials to be further integrated into multicompartmental systems capable of hierarchical chemo-mechano-chemical feedback responses. These responses no doubt represent only a small sample of the chemomechanical feedback behaviors waiting to be discovered in synthetic materials, and enable us to envision nearly limitless possibilities for designing multiresponsive, multifunctional, self-adapting materials and systems.
生物体是一系列动态、整合的自适应过程的集合：它不仅持续响应温度、阳光、营养等环境特征的不断变化，而且通过协调细胞、组织、器官和网络之间的反馈层次结构来实现这一点，所有这些都在不断相互适应。其根本是最基本的自适应过程之一：化学和力学之间的持续拔河，将化学信号与大分子、纤维、网格和膜的无尽重新配置交织在一起。在本教程中，我们探讨了这种化学机械反馈——作为连接大小和时间尺度的固有动态、迭代过程——如何以及已经在合成材料中被类似地激发，以产生迷人的复杂多尺度响应行为多样性。我们讨论了如何设计化学动力学和结构来在单个块状材料内产生刺激诱导的 3D 时空波和地形图案，以及内部动力学和表面大范围不稳定性之间的反馈如何进一步产生更高阶的屈曲和皱纹图案。基于这些现象，我们展示了如何将更高水平的反馈和时空复杂性编程到混合材料中，以及这些机制如何使混合材料进一步集成到能够进行层次化化学机械化学反馈响应的多隔室系统中。这些响应无疑代表了在合成材料中等待被发现的化学机械反馈行为的一小部分，使我们能够设想出设计多响应、多功能、自适应材料和系统的几乎无限的可能性。
