摘要 Abstract

当前，越来越多的研究者们开始探索如何制备特征尺寸处于介观范围（几十纳米到几百微米之间）的复杂三维结构，以通过化学、形态学和三维结构来控制材料系统的性质和构建器件的功能。然而，现有的三维组装/制造方法只适用于有限的材料类别和/或三维几何形状。在本次讲座中，我将介绍一种基于力学引导的组装方法。该方法通过控制屈曲，将预先制备好的图案化二维微/纳米级前驱体材料转变为复杂的三维微/纳米构型（前驱体材料可通过成熟的半导体技术轻松形成）。该方法适用于多种材料（如半导体、聚合物、金属和陶瓷）及其异构集成，尺度跨度从100纳米到10厘米不等。为了丰富该组装方法可实现的三维几何形状，我们设计了一组力学驱动的设计策略，如二维原型的切割/折叠设计、异质基底设计和控制加载路径的形态变化策略。在本次讲座中，我还将介绍一系列用于后屈曲分析的力学模型，以及将目标三维拓扑映射到未知二维前驱体图案的反向设计方法，为精确三维组装提供重要的理论基础。基于力学引导的组装方法与先进的制造/加工技术兼容，具有多功能性，能够将各种现有二维微系统转变为三维构型，为新型功能器件的开发提供了独特的设计选择。在讲座的最后，我将展示部分案例，包括与类器官/组织/器官形态一致的集成生物医学器件、能够高效收集低频振动能量的三维微机电系统（3D MEMS）、仿生电子系统及三维微流体器件。

A rapidly expanding research area involves the development of routes to complex 3D structures with feature sizes in the mesoscopic range (that is, between tens of nanometres and hundreds of micrometres). A goal is to establish methods to controll the properties of materials systems and the function of devices constructed with them, not only through chemistry and morphology, but also through 3D architectures. However, existing approaches of 3D assembly/fabrication are only compatible with a narrow class of materials and/or 3D geometries. In this talk, I will introduce a mechanics-guided assembly approach that exploits controlled buckling for constructing complex 3D micro/nanostructures from patterned 2D micro/nanoscale precursors that can be easily formed using established semiconductor technologies. This approach applies to a very broad set of materials (e.g., semiconductors, polymers, metals, and ceramics) and even their heterogeneous integration, over a wide range of length scales (e.g., from 100 nm to 10 cm). To enrich the class of 3D geometries accessible to the proposed assembly approach, we devised a set of mechanics-driven design strategies, such as kirigami/origami designs of 2D precursors, heterogeneous substrate designs and loading-path controlled shape morphing strategies. I will also introduce a series of mechanics models for the direct postbuckling analysis, as well as inverse design methods that map target 3D topologies onto unknown 2D precursor patterns, which could provide an important theoretical foundation of the rational 3D assembly. The compatibility of the approach with the state-of-the-art fabrication/processing techniques, along with the versatile capabilities, allow transformation of diverse existing 2D microsystems into 3D configurations, providing unusual design options in the development of novel functional devices. I will demonstrate a few examples in this presentation, including biomedical devices conformally integrated with organoids/tissues/organs, 3D MEMS capable of efficient energy harvesting of low-frequency vibration, bioinspired electronic systems, and 3D microfluidic devices.