Substrate Wetting Agents

 

 

Wetting is defined as the displacement of one fluid by another on a solid surface. There are three types of wetting phenomena: ① Adhesional Wetting (Sticking) ② Immersional Wetting (Soaking) ③ Spreading Wetting

 

 

Surfactants can render high-energy solid surfaces hydrophobic and lipophilic, while also enabling low-energy solids to be wetted by high-surface-energy liquids. Such surfactants are known as Wetting Agents.

 

 

Wetting involves changes in surface tension and interfacial tension; its essence is a process of surface displacement. It is determined by the relationship between three factors: the surface tension of the liquid, the surface tension of the solid, and the liquid-solid interfacial tension.

 

In coatings and inks, wetting transforms pigment particles from a lyophobic (liquid-fearing) state to a lyophilic (liquid-loving) state. Wetting agents wet the pigment particles as well as the newly formed interfaces created during grinding, thereby improving the efficiency of pigment comminution.

 

Dispersion, on the other hand, refers to the process of keeping the finely ground pigment particles suspended stably in the dispersion medium. This prevents sedimentation, floating, flooding, and delamination.

 

Since wetting facilitates dispersion and dispersion relies on wetting, the combined term Wetting and Dispersing Agent is commonly used.

 

 

Spreading Wetting involves a change in surface free energy. This includes the heat of adsorption and entropy changes generated by the directional adsorption of liquid molecules onto the solid surface. The primary factors influencing wetting are the composition of the adsorbed compounds at the solid/liquid interface, as well as their adsorption density and orientation. The smaller the solid/liquid contact angle, the better the wetting effect.

 

Leveling is a kinetic movement—the process by which a coating achieves a smooth and flat state on a substrate. Its driving force is the sum of various energies, primarily surface tension. (Note: Higher surface tension generally provides stronger driving force for flow, though balance is required to prevent cratering).

 

 

 

Wuhan Bright Chemical Co., Ltd. supplies Alkynediol-based substrate wetting agents.