Laser printing hierarchical structures with the aid of controlled capillary-driven self-assembly
Laser printing hierarchical structures with the aid of controlled capillary-driven self-assembly
复制标题
借助受控毛细管驱动自组装激光打印分层结构
DOI：
10.1073/pnas.1503861112
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发表时间：
2015-06-02
影响因子：
11.1
通讯作者：
Gu, Min
中科院分区：
文献类型：
--
作者：
Hu, Yanlei;Lao, Zhaoxin;Gu, Min
意义我们提出了一种策略，通过激光打印毛细管辅助自组装（LPCS）实现可设计的层次功能结构。超快激光打印应用于构建单元块，毛细力作为驱动力进行微调。通过控制柱的空间排列、高度、直径和蒸发工艺，成功地制备了各种结构。这些LPCS结构选择性捕获和释放微物体的能力表明在化学，生物医学和微流体工程领域具有巨大的潜在应用。毛细管力通常被认为是有害的，因为它可能在制造过程中对微米/纳米结构造成不期望的变形或甚至破坏，因此已经做出了许多努力来消除其负面影响。从另一个角度来看，毛细作用力可以巧妙地用于构建特定的复杂结构。在这里，我们提出了一种激光打印毛细管辅助自组装策略，用于制造规则的周期性结构。首先通过局部飞秒激光聚合产生微尺度柱，随后在蒸发液体中的受控毛细管力的帮助下组装成周期性的分层结构。空间布置、支柱高度和蒸发工艺易于调整，以实现具有各种几何形状的可设计有序组件。组装的可逆性也被揭示通过打破分子间的力和弹性站立力之间的平衡。我们进一步证明了分层结构作为选择性捕获和释放微粒的重要工具的功能，为微物体原位运输系统的开发开辟了潜力。
Significance We propose a strategy to realize designable hierarchical functional structures via laser printing capillary-assisted self-assembly (LPCS). Ultrafast laser printing is applied for building unit blocks and capillary force is finely tuned as driving force. Diverse structures are successfully fabricated by controlling the spatial arrangements, heights, diameters of pillars, and the evaporation process. The ability of these LPCS structures to selectively trap and release microobjects suggests enormous potential applications in the fields of chemistry, biomedicine, and microfluidic engineering. Capillary force is often regarded as detrimental because it may cause undesired distortion or even destruction to micro/nanostructures during a fabrication process, and thus many efforts have been made to eliminate its negative effects. From a different perspective, capillary force can be artfully used to construct specific complex architectures. Here, we propose a laser printing capillary-assisted self-assembly strategy for fabricating regular periodic structures. Microscale pillars are first produced by localized femtosecond laser polymerization and are subsequently assembled into periodic hierarchical architectures with the assistance of controlled capillary forces in an evaporating liquid. Spatial arrangements, pillar heights, and evaporation processes are readily tuned to achieve designable ordered assemblies with various geometries. Reversibility of the assembly is also revealed by breaking the balance between the intermolecular force and the elastic standing force. We further demonstrate the functionality of the hierarchical structures as a nontrivial tool for the selective trapping and releasing of microparticles, opening up a potential for the development of in situ transportation systems for microobjects.