人造玫瑰花花瓣的微结构分布与水滴黏附性质的关系

本文采用模板印刷法制备得到了“人造玫瑰花花瓣”，即具有玫瑰花花瓣结构的PDMS薄膜，通过对该薄膜逐级拉伸改变微观结构的分布；采用环境扫描电镜（ESEM）观察了不同拉伸程度下薄膜表面微观结构的变化，采用高敏感性微电力学天平测试了样品表面微观结构变化过程中水滴的粘附力，分析了微观结构分布与水滴粘附性质的关系；采用接触角测量仪表征不同拉伸条件下薄膜的浸润性.实验结果表明随着PDMS薄膜被逐次拉伸，单位面积内玫瑰花花瓣乳突的数目减少，纳米褶皱面积不断增加，而纳米级褶皱结构尺寸随着拉伸基本上不发生变化，直到样品破坏；与微观结构变化相对应的，该表面对水滴的粘附力先增大后减小，直到该表面彻底破坏.由此可见，微米结构及纳米结构的分布是影响玫瑰花花瓣对水滴粘附的主要因素.

Effects of the Distribution of Micropapillae with Nanofolds on the Adhesive Property of Artificial Red Rose Petals

Many biological organism surfaces exhibit amazing characters. An intriguing example is the red rose petals, which is famous with its “petal effect” (i.e. the water droplet adhesion effect). Numerous studies have revealed that these interesting characters of the biological surfaces are attributed to their special wettabilities with the combination of unusual micro/nano- hierarchical structures and chemical composition. In this article, the “petal effect”was reproduce on an “artificial red rose petal”— a superhydrophobic PDMS film with the same hierarchical rough structures of red rose petals. The surface adhesive effect was characterized by the high-sensitivity microelectromechanical balance system, and the effects of micro- and nanostructure on the adhesive property of “artificial red rose petals” was investigated by altering the stretch stage. The morphology of the “artificial red rose petals” at different stage were observed by environmental scanning electron microscope (ESEM), and the wettability was characterized by the apparent contact angle. The experimental results show that surface hydrophobicity can be enhanced by the nano-scaled structure and the high adhesive force is mainly caused by the micro- and nano-scaled structure. It is believed that this work will provide us a new avenue to further understand the wettablilty of solid surface and to design novel microfluidic devices in a wide range of applications.