The electrically neutral system of low-temperature plasma contains active particles such as electrons, ions, free radicals, excited molecules and atoms, as well as ultraviolet radiation. These active particles act on the surface of the material, causing surface etching, cross-linking, introduction of functional groups, and polymerization.

The Influence of Low Temperature Plasma Treatment on Material Surface

The effects of low-temperature ion treatment on the surface of materials can be divided into etching, functional group implantation, crosslinking reaction, polymerization deposition, etc.

(1) Etching

The etching effect of low-temperature plasma on material surfaces can be divided into two types. One is physical sputtering, which means that ions in the plasma system collide non elastically with atoms on the material surface to obtain energy and be in an excited state, thereby detaching from the material surface; Another type is chemical etching, which mainly involves the chemical reaction of active particles in low-temperature plasma on the surface of materials, causing molecules on the surface to generate small molecule gaseous volatiles such as H2O, CO, CO2 through chemical reactions, thereby causing polymer degradation and weight loss. Ions in low-temperature plasma only have low energy, so chemical etching plays a major role in etching the material surface in these two types of etching processes

(2) Implant functional groups

When the working atmosphere contains gases such as O2, N2, CF4, etc., active particles containing oxygen, nitrogen, and fluorine will be present in the obtained low-temperature plasma. These active particles act on the surface of the material, activating it and introducing new functional groups, thereby changing its surface structure and improving its surface properties.

(3) Crosslinking reaction

According to literature reports, when using inert gases such as pure He and pure N2 as the working atmosphere, low-temperature plasma treatment of materials is more likely to trigger cross-linking reactions on their surfaces. When the material obtains a cross-linking layer, its mechanical properties, solubility, and corrosion resistance are all improved.

(4) Aggregation sedimentation

The active particles in low-temperature plasma collide with the gaseous elements introduced into the working area, causing them to undergo chain breaking reactions and form free radicals. These free radicals then undergo merging reactions, resulting in the deposition of monomer atoms on the material surface. Compared with conventional polymerization reactions, low-temperature plasma polymerization deposition has unique advantages, such as less limitation in monomer selection, controllable deposition film thickness, and wide applicability to materials. Currently, many scholars are using it for depositing organic silicon and metal organic compounds on material surfaces.

The influence of plasma treatment on the surface of materials is mainly achieved through the interaction between particles and the material surface, including surface deposition, surface cleaning and etching, implantation of functional groups, and surface cross-linking. Low temperature plasma pretreatment causes a series of physical and chemical changes on the surface of materials, thereby improving their surface properties to meet different production application requirements.