Harnessing Photochemical Shrinkage in Direct Laser Writing for Shape Morphing of Polymer Sheets
Harnessing Photochemical Shrinkage in Direct Laser Writing for Shape Morphing of Polymer Sheets
复制标题
DOI：
10.1002/adma.201703024
复制
发表时间：
2017-11-13
影响因子：
29.4
通讯作者：
Daraio, Chiara
中科院分区：
文献类型：
--
作者：
Bauhofer, Anton A.;Krodel, Sebastian;Daraio, Chiara
结构在响应外部刺激时改变其形状，为更有效和通用的3D对象生产提供了可能性。直接激光写入（DLW）是一种基于双光子聚合的技术，可以制造具有复杂三维几何形状的微结构。在这里，研究表明DLW中的聚合收缩可以用来创建具有局部可控残余应力的结构，从而实现可编程的自弯曲行为。为了证明这一概念，平面和3d结构的薄片被预先编程成仿生形状（莲花和鲨鱼皮）。通过微尺度实验，确定了控制自弯曲行为的基本机制。在此基础上，提出了一种定量预测薄板弯曲曲率的解析模型。所提出的方法可以简单地制造具有复杂几何形状和精确可控形状变形潜力的物体，同时大大减少了在平方厘米量级的大面积上生产3D分层微结构所需的制造时间。
Structures that change their shape in response to external stimuli unfold possibilities for more efficient and versatile production of 3D objects. Direct laser writing (DLW) is a technique based on two-photon polymerization that allows the fabrication of microstructures with complex 3D geometries. Here, it is shown that polymerization shrinkage in DLW can be utilized to create structures with locally controllable residual stresses that enable programmable, self-bending behavior. To demonstrate this concept, planar and 3D-structured sheets are preprogrammed to evolve into bio-inspired shapes (lotus flowers and shark skins). The fundamental mechanisms that control the self-bending behavior are identified and tested with microscale experiments. Based on the findings, an analytical model is introduced to quantitatively predict bending curvatures of the fabricated sheets. The proposed method enables simple fabrication of objects with complex geometries and precisely controllable shape morphing potential, while drastically reducing the required fabrication times for producing 3D, hierarchical microstructures over large areas in the order of square centimeters.