荷叶表面纳米结构与浸润性的关系

Effects of Chemical Composition and Nano-structures on the Wetting Behaviour of Lotus Leaves

通过烘烤、化学萃取及物理剥除等方法改变荷叶表面的纳米结构和化学组成,在环境扫描电镜(ESEM)和全反射红外光谱(ATR)对样品的微观形貌和化学组成进行表征的基础上,为消除其它外界因素影响样品的真实微观形貌,进一步采用原子力显微镜(AFM)进行了表征.通过测量不同处理方法所得样品的表观接触角表征了样品的浸润性质.结果表明,荷叶表面的蜡质是产生表面疏水性的根本原因,其微米级结构放大了其疏水性,而纳米结构是导致其表面高接触角、低滚动角,即"荷叶效应"的关键原因.

Anneal,chemical extraction,stripping were used to change the chemical composition and microstructure on the surface of the lotus leaf.The morphology and chemical composition of samples were characterized by environmental scanning electron microscope（ESEM） and total reflection infrared spectroscopy（ATR）.Besides,atomic force microscope（AFM） was further used to avoid other external factors affecting the real morphology of samples.The sample wettability was characterized by the apparent contact angle.The results show that surface hydrophobicity is mainly caused by the wax on lotus leaf surface.The micro-scaled structure enhances its hydrophobicity,and the nano-scaled structure take important role in low tilt angle.