Department of Mechanical Engineering, Massachusetts Institute of Technology Cambridge, Massachusetts, 02139, United States.
Small. 2014 Jun 25;10(12):2487-94. doi: 10.1002/smll.201303051. Epub 2014 Mar 20.
A multifunctional surface that enables control of wetting, optical reflectivity and mechanical damage of nanostructured interfaces is presented. Our approach is based on imprinting a periodic array of nanosized cones into a UV-curable polyurethane acrylate (PUA), resulting in a self-reinforcing egg-crate topography evenly distributed over large areas up to several cm(2) in size. The resulting surfaces can be either superhydrophilic or superhydrophobic (through subsequent application of an appropriate chemical coating), they minimize optical reflection losses over a broad range of wavelengths and a wide range of angles of incidence, and they also have enhanced mechanical resilience due to greatly improved redistribution of the normal and shearing mechanical loads. The transmissivity and wetting characteristics of the nanoscale egg-crate structure, as well as its resistance to mechanical deformation are analyzed theoretically. Experiments show that the optical performance together with self-cleaning or anti-fogging behavior of the inverted nanocone topography is comparable to earlier designs that have used periodic arrays of nanocones to control reflection and wetting. However the egg-crate structures are far superior in terms of mechanical robustness, and the ability to replicate this topography through several generations is promising for large-scale commercial applications where multifunctionality is important.
本文提出了一种能够控制纳米结构界面润湿性、光学反射率和机械损伤的多功能表面。我们的方法是通过在紫外光固化的聚氨酯丙烯酸酯（PUA）中压印纳米尺寸的锥形周期性阵列，从而在几平方厘米（2）大小的大面积上均匀分布自增强的蛋盒状形貌。所得表面可以是超亲水的或超疏水的（通过随后施加适当的化学涂层），它们在宽波长范围和宽入射角范围内最小化光反射损耗，并且由于正常和剪切机械负载的重新分配得到极大改善，因此具有增强的机械弹性。从理论上分析了纳米蛋盒结构的透光率和润湿性特性及其对机械变形的抵抗力。实验表明，倒置纳米锥形形貌的光学性能以及自清洁或防雾性能可与先前使用纳米锥形周期性阵列来控制反射和润湿性的设计相媲美。然而，在机械鲁棒性方面，蛋盒结构要优越得多，并且通过几代人的复制这种形貌的能力对于需要多功能性的大规模商业应用具有广阔的前景。
