Low temperature plasma treatment technology has become a research hotspot in the field of material surface modification in recent years due to its environmental friendliness, high efficiency and no negative impact on the material matrix. This technology utilizes the energy of the plasma to act on the surface of the material in three main ways, including light radiation, neutral molecular flow and ion flow. The spectral range of low temperature plasma is wide, including visible light, ultraviolet light and infrared light. Among them, ultraviolet light is of special importance because it can not only be absorbed by the surface of the material, but also induce the formation of free radicals on the surface. The high chemical activity of free genes in low-temperature plasma can effectively react with molecules on the surface of materials. These reactions include dehydrogenation, oxidation and addition, which fundamentally change the chemical composition and physical properties of the material surface. The occurrence of these reactions is partly due to the free radicals produced by the decomposition of neutral particles on the surface, which can trigger a series of surface chemical reactions. At the same time, when the ion flow collides with the surface of the material, it will not only cause surface etching, but also lead to local heating of the surface. This heating effect can promote the surface chemical reaction and further enhance the modification effect of the material surface. Similar to neutral particles, ion flow can also trigger a series of surface reactions, although the mechanism may be slightly different. These three mechanisms work together to promote the modification process of the material surface, making plasma technology an efficient and multifunctional surface treatment method.

The principle of plasma treatment process

As a dry modification process, plasma surface treatment has attracted much attention in the field of surface engineering due to its advantages of precise control of material surface properties. The plasma generated by the plasma discharge device reacts with the surface of the material to achieve surface modification, which involves two main reaction mechanisms : chemical reaction and physical reaction.

Chemical reaction

In chemical reactions, the commonly used discharge media include air, O2, H2, etc., and a large number of high-energy plasmas are generated during the discharge process to bombard the polyurethane surface. Because the energy in the plasma is much larger than the binding bond energy of the material molecules, the molecular bonds on the surface of the material are broken, and the polar groups generated in the plasma dielectric barrier discharge are combined and recombined, and different active groups are introduced, so as to realize the regulation of surface properties. This chemical reaction is a targeted method, which can realize the fine adjustment of the surface chemical structure and provide the feasibility for practical application.

Reaction of the material

On the other hand, the physical reaction mainly uses inert gases such as Ar and He as the medium. In theory, when the gas molecules in the plasma interact with the surface of the material, they do not directly participate in the chemical reaction, but excite the surface molecules by energy transfer. This energy transfer allows the surface molecules to obtain sufficient energy, which is converted into an activated state and generates a chain free radical. These newly generated chain radicals are further involved in the reaction on the surface, and they can oxidize with oxygen in the air or react with each other on the surface of the material. These reactions may lead to the formation of new chemical bonds between surface molecules, such as cross-linked structures, thereby forming a new layer of chemical structure on the surface of the material to achieve surface modification of the material. At the same time, the high-energy particles such as ions and electrons generated after ionization impact the surface of the material, realizing the change of surface roughness and having a positive impact on the modification effect of the material surface.

In summary, plasma treatment technology achieves flexible adjustment of material surface properties by regulating different reaction mechanisms, and provides a variety of solutions for various application scenarios. Plasma treatment technology, as an efficient and multifunctional surface engineering technology, has shown its unique value and wide application potential in many industries. The reason why the plasma treatment technology is so efficient is largely due to the complex physical and chemical phenomena involved in the plasma activation process. Under the action of plasma, a series of micro-level changes can occur on the surface of the material, including the reorganization of molecular structure, the fracture and formation of chemical bonds, and the introduction of new functional groups. These changes not only change the chemical properties of the surface of the material, but also may lead to the adjustment of the deep structure of the material, so as to realize the comprehensive optimization of the material properties.