Understand some knowledge of surface tension

Some basic knowledge of surface tension What is surface tension?

As we all know, we can explain the properties of liquids based on the mutual attraction between molecules. This attraction between molecules is called molecular cohesion or van der Waals force. The surface tension, interfacial tension and similar phenomena are the basic physical phenomena used to explain the cohesion of molecules.

Specifically, the force of the molecules that make up the liquid on the surface is different from that in the body. The forces on the molecules in the body are symmetrical and balanced. The molecules on the surface are attracted by the molecules in the body without a counterbalance force. That is to say, it receives a force that is pulled into the body. In other words, trying to reduce the surface area, so that this unbalanced state tends to equilibrium. The thermodynamic statement is: To minimize the surface energy of this system, this force is called "surface tension", which is also called the free energy per unit area (J / m2), that is, the formation or expansion of the interface per unit area The minimum energy required. Its value is consistent with the surface tension (N / m). Due to the habit, surface tension is commonly used to express surface free energy, which plays a vital role in the physical and chemical phenomena of the liquid surface. In daily life, dewdrops on lotus leaves in the morning and the curved water surface in cups are all surface tension phenomena.