1. Definition of Wetting

Wetting: refers to the process in which one fluid on a solid surface is replaced by another fluid, called wetting. There are three phenomena of wetting: ① wetting, ② wetting, ③ spreading.

2. Surfactants are the key to wetting

It can make the surface of high-energy solids hydrophobic and oleophilic, and can also wet low surface energy solids with high-energy liquids. This type of surfactant is a wetting agent.

3. Wetting effect

It is the process of changes in surface tension and interfacial tension, essentially a surface displacement engineering. The wetting effect is determined by the relationship between the surface tension of the liquid, the surface tension of the solid, and the interfacial tension between the liquid and solid.

Wetting is the process of transforming pigment particles from hydrophobic to hydrophilic. Wetting agents can wet pigment particles as well as the newly generated particle interfaces after grinding, which can improve the efficiency of pigment grinding and crushing. And dispersion refers to the ability of finely ground pigment particles to stably float and remain in the dispersing medium. No adverse phenomena such as sedimentation, floating color, blooming, or layering occur. From this, it can be seen that there is dispersion in wetting, and there is wetting in dispersion, hence the name wetting dispersant.

4. The relationship between spreading wetting and leveling

Spread wetting is a change in surface free energy. This type of free energy includes the change in adsorption heat and entropy generated by the directed adsorption of liquid molecules on solid surfaces. The main factor causing wetting is the composition of the adsorbed compounds at the solid/liquid interface, the adsorption density and orientation of the substance at the interface. The smaller the solid/liquid contact angle, the better the wetting effect. Leveling is a form of movement. It is the process of achieving a smooth and even state of coating on the substrate. Its driving force should be the sum of various energies. The main driving force is surface tension, and the higher the force, the better the flow leveling.