Optimization Of Shielding Effectiveness And Antioxidant Properties Of Copper Thin Film Composites Deposited On Polyester Fabric

Electromagnetic radiation not only threatens people's health, but also has side effect on industrial production and military activities. It is getting more and more concerns about how to reduce the harm of electromagnetic radiation to our daily life. The paper briefly stated the necessity and preparation method of developing electromagnetic shielding materials and chose efficient and environmentally-friendly magnetron sputtering method. Metal film is deposited on two sides of polyester fabric. It improves shielding effectiveness of polyester fabric.The paper prepares double-sided textile shielding material of copper?copper film is deposited on two sides of substrate?. Shielding effectiveness of double-sided textile shielding material of copper and single-sided textile shielding material of copper?copper film is deposited on one side of substrate? are compared on the same process condition. The results showed that the shielding effectiveness of double-sided textile shielding material of copper is 20-30 dB higher than single textile shielding material of copper. This is because interface number of wave impedance difference of double-sided textile shielding material of copper is two times as much as single-sided textile shielding material of copper. Electromagnetic characteristics of double-sided and single-sided textile shielding material are studied. Result shows that the shielding effectiveness of single-sided textile shielding decreases with the increase of electromagnetic wave frequency. However, double-sided textile shielding material has opposite situation.Effects of sputtering process and substrate structure on shielding effectiveness of double-sided textile shielding materials of copper were studied. Effect of coating time about sputtering process on shielding effectiveness of double-sided textile shielding material of copper is studied. Shielding effectiveness of double-sided textile shielding material of copper on the different coating time is tested. Testing result shows that the shielding effectiveness of double-sided textile shielding material of copper improves with the increase of coating time. Effects of surface morphology, substrate structure and square meter weight about substrate structure on shielding effectiveness of double-sided textile shielding material of copper is studied. Research result shows that shielding effectiveness of ZnO/Cu composite textile shielding material is 5-10 dB higher than double-sided textile shielding material of copper. This is because original surface morphology of polyester fiber is improved after buffer layer ZnO is introduced. So copper film deposits on the surface of PET fiber with ZnO thin film is easier to form continuous network structure. Thus, the copper film has greater conductive property. Copper film is deposited on the double-sided of spunbonded nonwoven fabric, woven fabric and knitted fabric. Shielding effectiveness of three kinds of textile shielding materials with different substrate structure is SE_nonwoven?SE_woven?SE_knitted. Shielding effectiveness of double-sided textile shielding material with 300g/m2, 400g/m2 and 500g/m2 is tested. Testing result shows that the shielding effectiveness of double-sided textile shielding material increases with the increase of square meter weight.In order to improve the antioxidant properties of copper film, Al₂O₃ thin film is coated on the surface of double-sided copper film to prpeare Cu/Al₂O₃ composite thin films. Double-sided copper thin film and Cu/Al₂O₃ composite thin films are placed in the same room temperature environment for 150 days. Surface morphology, element content and shielding effectiveness of the samples are tested. Testing result shows that small crack appears on the surface of the copper thin film. Content of oxygen element increases from 0% to 8.85%, and the shielding effectiveness decreases from 80 dB to 32 dB. Overall morphology of Cu/Al₂O₃ composite thin films has not changed, the content of oxygen element increases from 2.73% to 4.24%, shielding effectiveness only decreases 8dB. This shows that the Cu/Al₂O₃ composite thin films has better antioxidant properties.