溶胶凝胶法制备仿生超疏水性薄膜

通过溶胶-凝胶(Sol-Gel)法和自组装(Self-assembled)制备了具有超疏水性的薄膜, 水滴在该薄膜上的平衡静态接触角为155°～157°, 滑动角为3°～5°. 通过扫描电子显微镜(SEM)观察薄膜微观表面, 发现该薄膜表面分布了双层结构(Binary structure)的微纳米粗糙度的微凸体, 上表层微米微凸体的平均直径为0. 2 μm, 下表层纳米微凸体的平均直径约为13 nm, 其分布与荷叶表面的结构极其相似. 用X射线光电子能谱(XPS)对薄膜表面元素进行了成分分析, 结果表明, 其表面存在大量的F, Cl等元素, 它能显著降低薄膜表面的表面能. 薄膜超疏水性的原因可能是, 通过硅片经溶胶粒子表面制备的薄膜具有合适的表面粗糙度, 再经过全氟辛基三氯甲硅烷(FOTMS)化学修饰后, 薄膜表面能进一步降低, 这两个条件的有机结合就使得薄膜产生了超疏水性.

Preparation of Biomimetic Superhydrophobic Silica Film by Sol-gel Technique

A superhydrophobic silica film was prepared by means of sol-gel and self-assembly techniques, with a very high water contact angle (155°～157°) and a small sliding angle (3°～5°), making water droplet move readily on the surface. The film surface morphologies were observed with scanning electron microscope, and the elements on surface were determined by X-ray photoelectron spectroscopy. It was found that there were many microconvexities with binary structure uniformly distributed on the surface atop of the film with the average diameter of about 0. 2 μm and nanoconvexities on the lower surface layer of the film with the average diameter of about 13 nm, and the film surface structure was similar to that of lotus surface. Many elements such as F and Cl were observed on the film surface, which could make the film surface energy decreased dramatically. The possible reason of leading to superhydrophobic properties on the as-prepared film is due to form an appropriate surface roughness after sol-gel method, and its surface energy will be further decreased after being modified with perfluorooctyltrichloromethoxysilane (FOTMS). These two formed conditions of surface roughness and low surface energy on the film will make the film formed on silicon exhibit good superhydrophobic properties.