Characterization of Multi-scale Morphology and Superhydrophobicity of Water Bamboo Leaves and Biomimetic Polydimethylsiloxane (PDMS) Replicas
Characterization of Multi-scale Morphology and Superhydrophobicity of Water Bamboo Leaves and Biomimetic Polydimethylsiloxane (PDMS) Replicas
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DOI：
10.1016/s1672-6529(14)60152-9
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发表时间：
2015-10-01
影响因子：
4
通讯作者：
Ren, Luquan
中科院分区：
文献类型：
--
作者：
Guan, Huiying;Han, Zhiwu;Ren, Luquan
研究了水竹叶及其仿生复制品的表面形貌和润湿性。利用扫描电子显微镜（SEM）和共聚焦激光扫描显微镜（CLSM）对样品的形貌结构进行了表征。通过接触角测量对样品的静态润湿性进行了评估，而通过高速摄像系统对动态润湿性进行了分析。用Cassie模型解释了WBL的润湿机理。通过使用PDMS大面积（5 cm x 3 cm）复制WBL表面微结构来制造人工表面。结果表明，该叶片表面的主要结构特征为亚毫米级沟槽阵列、微米级乳突和具有3D表皮蜡雕层次结构的叠加层，静态水接触角（WCA）为151 ° ± 2 °，水滑动角（WSA）为4 ° ~ 6 °，表明该叶片表面具有超疏水性。蜡膜与WBL表面微观结构的结合赋予了其优异的超疏水性能。具有从亚毫米到微米尺度范围的特征的复杂层次图案被很好地再现。不存在纳米结构的原因是在固化过程中植物蜡的熔化。人工WBL和阴性PDMS复制品上的WCA值分别为146度+/-3度和137度+/-2度，证明了优选的疏水性。天然叶片和人造叶片之间润湿行为的差异源于叶片表面上三维蜡投影的化学和结构的不准确复制。然而，与光滑PDMS参考相比，转移到复制品的叶的形态特征显著改善了复制品的疏水特性。该研究为仿生设计和构建大面积粗糙诱导疏水防粘材料表面提供了启示。
The morphology and wettability of Water Bamboo Leaves (WBL) and their biomimetic replicas were investigated. The particular morphology structures of samples were characterized by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). The static wettability of samples was assessed by contact angle measurements, while the dynamic wettability was analyzed by high speed camera system. The wettability mechanism of WBL was also explained by Cassie model. Artificial surfaces were fabricated by duplicating WBL surface microstructures using PDMS in large area (5 cm x 3 cm). The results show the main structure characteristics of this leaf surface are sub-millimeter groove arrays, micron-scale papillae and a superimposed layer with 3D epicuticular wax sculptures hierarchical structure, and the static Water Contact Angle (WCA) of 151 degrees +/- 2 degrees and Water Sliding Angle (WSA) of 4 degrees-6 degrees indicate that WBL surface is superhydrophobic. The combination of wax film and microstructure of WBL surface gives its surface excellent superhydrophobic property. Complex hierarchical patterns with features from sub-millimeter to micron-scale range are well reproduced. The reason for the absence of nanostructures is melting of plant epiderrnal wax during the curing process. The WCA values on artificial WBL and negative PDMS replica are 146 degrees +/- 3 degrees and 137 degrees +/- 2 degrees, respectively, demonstrating preferable hydrophobicity. Differences in wetting behavior between natural leaves and artificial leaves originate from an inaccurate replication of the chemistry and structures of the three-dimensional wax projections on the leaf surface. Nevertheless, the morphological features of the leaf transferred to the replica improve significantly the hydrophobic properties of the replica when compared with the smooth PDMS reference. This study may provide an inspiration for the biomimetic design and construction of large area roughness-induced hydrophobic and anti-sticking material surface.