超快激光打印结合毛细力驱动的可调谐功能结构自组装及其应用

Micro/nano-manufacturing approaches can be divided into two methods: top-down and bottom-up. Top-down method can fabricate structures with complex geometry and various materials properties. However, it needs complex processing procedures and consumes long time and much money. Bottom-up method builds specific structures by assembling unit blocks, with the advantage of simplicity and high-speed. But the geometries of achieved structures are limited, and moreover, cannot be tunable. This proposal combines these two methods, and put forward a capillary force driven self-assembly method. This project will give play to the femtosecond laser based two-photon polymerization, and aim to manufacture tunable functional devices. The main research contents are list below. First, Analyzing the interfacial force properties and behaviors under micro/nano scale multi-force field coupling conditions. Realizing the stable self-assembly of diverse structure units by optimizing multi-dimensional parameters. Developing fabrication technologies of tunable functional structures based on flexible substrate and intelligent materials. Achieving large-area hierarchical structures by applying laser holography technique. Finally, exploring the application possibilities of the self-assembled structures in the field of micro-fluidics and chiral photonic devices. The proposed laser printing capillary force-driven self-assembly method has the ability of fabricating multi-scale, large-area functional structures, and possessing good prospect in industrial applications.

微纳米加工手段包括自上而下和自下而上两种技术途径。自上而下方法可以构建复杂造型和材料特性的结构，但是通常工艺过程复杂，耗时长且成本高；自下而上方法依靠基本单元逐级组装制造特定的结构，过程简单便捷，但是所获结构类型有限，形貌不可调谐。本项目将两种微纳制造手段相结合，提出一种毛细力驱动的微结构单元自组装方法，发挥飞秒激光双光子聚合技术三维复杂成型能力的优势，实现可调谐的功能器件制备。主要研究内容包括：分析微观尺度多力场耦合条件下基本结构单元的界面力学性能和行为；通过多维参数优化控制实现毛细力驱动的多样化结构单元的可靠自组装；发展基于柔性基底和智能材料的可调谐功能结构加工技术；利用激光全息技术实施大面积多级自组装结构的高效制备，并探索其在微流体和手性光子学等领域的应用。本项目提出的飞秒激光打印结合毛细力驱动自组装方法具备跨尺度大面积功能结构的加工能力，具有良好的产业化应用前景。

毛细力是在自然界中广泛存在的一种固液界面作用力。一般与体积相关的力，例如重力，随着尺寸的减小呈现三次方关系减小；而毛细力的大小随着尺度的缩小而成二次方关系减小；因此，在微纳米尺度下，毛细力的作用开始起主导作用。本项目将自上而下和自下而上两种微纳制造手段相结合，提出一种毛细力驱动的微结构单元自组装方法，发挥飞秒激光双光子聚合技术三维复杂成型能力的优势，实现可调谐的功能器件制备。本项目的主要研究内容包括：分析微观尺度多力场耦合条件下基本结构单元的界面力学性能和行为；通过多维参数优化控制实现毛细力驱动的多样化结构单元的可靠自组装；发展基于柔性基底和智能材料的可调谐功能结构加工技术；利用激光全息技术实施大面积多级自组装结构的高效制备。在项目开展期间，我们研究了不同类型结构单元（一维、二维）在毛细力驱动下的界面力学行为，在实验上实现了多种结构单元的毛细力驱动自组装；实现了仿毛细血管的超长、超薄管道毛细力驱动自组装制备；利用全息方法提升了自组装结构单元的加工效率，并对激光打印中的多维参数进行了优化；尝试利用柔性基底实现了自组装结构的形貌调谐；扩展了飞秒激光全息加工方法，实现了微管阵列和手性结构的快速制造；对柔性智能材料形状记忆聚合物和水凝胶进行了加工尝试。本项目提出的飞秒激光打印结合毛细力驱动自组装方法具备跨尺度大面积功能结构的加工能力，具有良好的产业化应用前景。