行走的“红绿灯”

The wettability of the solid surface is related to its microgeometry and physicochemical properties, which is determined by both the specific micro-geometry structure of the surface and the physicochemical properties of surface chemicals. The wettability is an important feature of the solid surface and can be measured quantitatively by the contact angle. It not only directly affects life activities of both animals and plants in nature, but also plays an important role in both human's daily life and industrial and agricultural production. The wettability of a solid surface can be measured by the contact angle of water. This popular science experiment discusses the superhydrophobic surface of lotus leaf, water strider and other living things, and expounds the principle of superhydrophobicity, so as to help people understand the origin and development of superhydrophobic materials in life. The superhydrophobic material was prepared by sol-gel method, and its superhydrophobic property was compared with the control surface. Finally, we carried out "traffic light" experiment by employing indigo carmine on the superhydrophobic material for people to feel the beauty and interest of chemistry, so as to stimulate their interest in chemistry, and further lead people to explore and think about the material science.

Keywords： Surface wettability ; Superhydrophobic material ; Indigo carmine ; Popular science experiment ; Interesting experiment