水烛叶表面的浸润性研究及其仿生表面的制备

Study on Wettability of Typha Angustifolia Leaves and Fabrication of Biomimetic Surfaces

研究了水烛叶及其仿生表面的形貌和浸润性.通过接触角测量仪(OCA)测得水烛叶的静态接触角为111.5°±2°,其聚二甲基硅氧烷(PDMS)仿生表面的接触角为148.8°±2°.通过扫描电子显微镜(SEM)对样品的表面微观形貌进行表征,发现水烛叶表面的主要由亚毫米级周期性沟槽,微米级点阵乳突和纳米级鳞屑状蜡质层组成.此外,通过Cassie模型分析了水烛表面的浸润性机理,水烛叶表面复杂的微观结构和蜡质层的结合使其表面具有较好的疏水性.利用PDMS复制了水烛叶表面的微结构,由SEM测试结果可知PDMS仿生表面达到了很好的复制效果,从亚毫米级到微米级范围的复杂分层结构得到很好的再现,然而纳米结构在固化过程中因为植物表面蜡质层的熔化导致无法被复制.水烛叶和PDMS仿生表面之间的浸润性差异源自于叶片表面上蜡质化学性质不稳定以及微观结构的差异.但是同平滑的PDMS相比,复杂的分层结构明显改善了其浸润性.该研究可为大面积制备疏水材料表面的仿生设计和构造提供参考.

The morphology and wettability of Typha angustifolia leaves and their biomimetic surfaces were studied in this paper.The static contact angle of the Typha angustifolia was measured by the contact angle meter (OCA) to be 111.5°±2°,and the contact angle of the Polydimethysiloxane (PDMS) bionic surface was 148.8°± 2°.The surface microscopic morphology of the sample was characterized by scanning electron microscopy (SEM).It was found that the surface of the Typha angustifolia leaf was mainly composed of sub-millimeter periodic grooves,micron-order lattice mastoids and nano-scale scaly wax layers.In addition,the wettability of the surface of the Typha angustifolia was analyzed by the Cassie model. The surface excellent hydrophobic was given by the complex microstructure of the surface of the Typha angustifolia leaf and the wax layer.The microstructure of the surface of the Typha angustifolia leaf was reproduced by PDMS.The SEM test results show that the PDMS bionic surface has a good replication effect, and the complex layered structure from sub-millimeter to micron range is well reproduced.However,the nanostructure cannot be replicated during the curing process due to melting of the wax layer on the surface of the plant.The difference in wettability between the Typha angustifolia leaf and the PDMS bionic surface is due to the instability of the waxy chemical properties on the surface of the leaf and the difference in microstructure.However,the complex layered structure significantly improves its wettability compared to smooth PDMS.A reference is provided for the bionic design and construction of large-area preparation of hydrophobic material surfaces.