Study On UV Ozone Modification Of Polymer Surface And Preparation Of Electromagnetic Shilding Film For Cockpit Cover

With the development of photovoltaic systems,transparent conductive materials have been widely used in displays,solar cells and architectural coatings due to their excellent optoelectronic properties,and they play a vital role in the optical window in the aerosapce industry as the heating electrodes for windows defogging and electromagnetic shielding films that reduce the radar coss-sectional area.As the optical window of the aircraft,the cockpit cover not only carries the pressure difference load inside and outside the cockpit and the structural requirements of bird collision and high-speed flight aerodynamic heat,but also can reduce the scattering of electromagnetic waves to achieve stealth effect.Since the canopy base is polymer and has a curved shape,it is required to prepare a film having a certain toughness at a low temperature while ensuring transmittance and electromagnetic shielding efficiency,so that only composite film composed of metal and metal oxide can be selected to achieve this purpose in the current transparent conductive film system.However,the poor bonding force between the metal film and the polymer is also an urgent problem to be solved in the field of transparent conductive film applications.In view of the above problems,this paper uses UV ozone modified Polymethylmethacrylate?PMMA?to improve the bonding strength between metal film and polymer.The modification principle is explained by surface morphologies,functional groups and hydrophilicity by means of AFM,ATR-FTIR and surface water contact angle.The composite structure of gold?Au?film and Titanium oxide?TiO₂?film is used as the electromagnetic shielding film of the canopy cover.The relationship between the thickness of the Au film and the transmittance and electromagnetic shielding efficiency is studied.It is found that the slight change of the thickness of the nanometer will cause significant changes in the properties of the film.TiO₂ thin films were prepared by RF magnetron sputtering under different oxygen flow rates and the morphology,chemical composition,transmittance and hardness of the films were characterized.Experimental results show that under the condition of power 100W,argon flow rate 20sccm and sputtering pressure 1.5Pa,7sccm oxygen flow rate is the best gas parameter for preparing TiO₂ film.Finally,based on the analysis of the transparent conductive mechanism of the composite film,the optical constant of the film is calculated by ellipsometry.Electromagnetic shielding films were prepared on PMMA substrates using TiO₂/Au/TiO₂ structure and Au/TiO₂ structure,respectively,and photoelectric properties were tested.The results show that the average transmittance of the film samples at¹1/30nm with the structure of Au/TiO₂ is⁷1%,and the electromagnetic shielding efficiency is lower than-20dB.Compared with the former structure,the transmittance is increased by⁵%,and the atomization problem caused by depositing TiO₂ film directly on the surface of PMMA can be solved,and the preparation process is simplified.