About plasma treatment technology in filter membrane surface modification
Issuing time:2023-12-22 10:57
Plasma treatment is a surface modification technology for filter membranes, and its main function is to enhance the performance of the filter membrane. The so-called plasma refers to an ionized gas state containing free electrons, ions, free radicals and neutral molecules. It is composed of high-energy particles. Plasma processing technology is to conduct low-pressure plasma discharge on membrane materials to produce active substances and high-energy particles. Interacts with the membrane surface at the molecular level, causing various changes in membrane properties.
By applying high-frequency electric fields or other energy sources to low-pressure gases to stimulate the ionization and dissociation of gas molecules, an ionized gas composed of charged particles (such as electrons, ions, free radicals and excited state substances) is formed. During plasma treatment, these high-energy Electrons and ions collide with gas molecules to produce a variety of reactive species, including free radicals (such as oxygen, nitrogen, and hydroxyl radicals), excited atoms, and ions.
The active substances formed by plasma discharge can interact with the surface of the filter membrane, destroy the chemical bonds on the surface and introduce new functional groups or change the existing surface chemical properties, thereby enhancing the reactive performance of the membrane surface. Plasma treatment can introduce specific Functional groups, or modify existing chemical bonds on the surface of the film. For example, if oxygen-containing gas is used during plasma treatment, oxygen free radicals can react with the surface, leading to the introduction of oxygen-containing functional groups to form hydroxyl (-OH) or carbonyl (-C= O) group, etc., or convert the methyl group (-CH3) on the membrane surface into a carboxyl group (-COOH), etc. This functionalization can change the surface properties of the membrane, such as hydrophilicity, surface energy, antibacterial properties or chemical properties. reaction performance.
Plasma treatment can also trigger cross-linking or polymerization reactions on the membrane surface. The reactive substances produced in the plasma can trigger chemical reactions between polymer chains, thereby forming covalent bonds, which can improve the mechanical strength and chemical stability of the filtration membrane. and durability. At the same time, it also has a cleaning effect on the membrane surface, because the reactive substances can interact with and remove organic pollutants, residual monomers or other impurities present on the surface. This cleaning effect can improve the purity and performance of the filtration membrane.
If viewed from a microscopic level, surface modification plasma treatment can change the surface topography, roughness and morphology of the filter membrane, mainly because it changes the polymer chain organization, promotes rearrangement, or induces material Cross-linking within the structure, etc. These microscopic changes can affect the membrane's filtration efficiency, pore size, and surface interaction with particles or liquids.
In short, plasma treatment technology is an effective way to improve the performance of filter membranes. This type of technology can precisely control the modification of the filter membrane surface at the molecular level, and can improve the filtration performance, selectivity, durability and compatibility of the filter membrane for specific applications.