Department of Mechanical Engineering, University of Michigan, 2350 Hayward Street, Ann Arbor, MI 48109-2125, USA.
Lab Chip. 2011 May 21;11(10):1831-7. doi: 10.1039/c0lc00724b. Epub 2011 Mar 30.
Scalable and cost effective patterning of polymer structures and their surface textures is essential to engineer material properties such as liquid wetting and dry adhesion, and to design artificial biological interfaces. Further, fabrication of high-aspect-ratio microstructures often requires controlled deep-etching methods or high-intensity exposure. We demonstrate that carbon nanotube (CNT) composites can be used as master molds for fabrication of high-aspect-ratio polymer microstructures having anisotropic nanoscale textures. The master molds are made by growth of vertically aligned CNT patterns, capillary densification of the CNTs using organic solvents, and capillary-driven infiltration of the CNT structures with SU-8. The composite master structures are then replicated in SU-8 using standard PDMS transfer molding methods. By this process, we fabricated a library of replicas including vertical micro-pillars, honeycomb lattices with sub-micron wall thickness and aspect ratios exceeding 50:1, and microwells with sloped sidewalls. This process enables batch manufacturing of polymer features that capture complex nanoscale shapes and textures, while requiring only optical lithography and conventional thermal processing.
可扩展且具有成本效益的聚合物结构及其表面纹理图案化对于工程材料性能（如液体润湿性和干附着力）以及设计人工生物界面至关重要。此外，高纵横比微结构的制造通常需要受控的深蚀刻方法或高强度曝光。我们证明，碳纳米管 (CNT) 复合材料可用作具有各向异性纳米级纹理的高纵横比聚合物微结构的母模。母模是通过垂直排列的 CNT 图案的生长、使用有机溶剂对 CNT 进行毛细浓缩以及 CNT 结构与 SU-8 的毛细驱动渗透来制造的。然后使用标准 PDMS 转移模塑方法在 SU-8 中复制复合母结构。通过该工艺，我们制造了包括垂直微柱、具有亚微米壁厚度和超过 50:1 的纵横比的蜂窝晶格以及具有倾斜侧壁的微井在内的一系列复制品。该工艺能够批量制造能够捕捉复杂纳米形状和纹理的聚合物特征，而仅需要光学光刻和常规热处理。
