Preparation And Performance Modulation Of SiO₂ Based Photothermal Superhydrophobic Coatings For Anti-icing Of Power Transmission Lines

Transmission lines in the power system are prone to a series of electrical accidents once icing occurs,and serious icing will also sharply increase the mechanical load of lines and towers and other support structures,causing mechanical accidents such as line breakage and tower collapse,affecting the safe operation of the power grid.Superhydrophobic materials have the advantages of delaying icing and reducing ice adhesion,which makes them one of the new protection means in the field of anti-icing of power transmission lines.Among the many studies on superhydrophobic coatings,SiO₂ nanomaterials-based ones are the most widely studied,but most of them have complicated synthesis processes and poor mechanical properties.To address the above deficiencies,this study used magnetic stirring to prepare superhydrophobic materials with excellent anti-icing performance as well as mechanical properties,and finally applied to the surface of transmission aluminum conductors for anti-icing performance study.The main research contents and conclusions of this paper are as follows.（1）The SiO₂/E₄₄/ODA/HDTMS composite superhydrophobic coatings were prepared by magnetic stirring and scraping.The effects of different SiO₂ contents on the hydrophobic properties of the coatings were investigated by CA and SA characterization methods,and the wear resistance and anti-icing properties of the coatings were tested respectively.The results of the above tests showed that the CA of the coating showed a trend of becoming larger and then smaller with the increase of SiO₂ content.When the content of epoxy resin E₄₄ is certain,it is difficult to form a complete coating if there is only a small amount of SiO₂,while too much will lead to cracking of the coating.When the SiO₂ content is 28%,CA reaches 158.2±0.5°and SA is 4.5±0.3°,at which point the hydrophobic effect is optimal.The SiO₂/E₄₄/ODA/HDTMS superhydrophobic coating can still maintain its superior superhydrophobic performance after30 grit impacts.In the anti-icing test,water droplets on bare aluminum were completely frozen at t=202 s,while the hydrophobic coating became completely opaque at t=363 s.The anti-icing performance of the coating was also demonstrated by the difference in the amount of ice cover on an uncoated section of the stranded aluminum wire compared to a coated section in application tests.The results indicate that the wear resistance and anti-icing properties of the coating are average,but the research methodology provides a basis for subsequent studies.（2）In order to improve the anti-icing performance of the coating further,an attempt was made to add photothermal conversion materials to the solution.In turn,MWCNTs/SiO₂/PDMS/PVDF superhydrophobic anti-icing coatings were prepared.The microscopic morphology of the coating surface was investigated by SEM and AFM characterization,and the chemical composition and chemical bonding of the coating were investigated by XPS,EDX and FTIR.The acid and alkali resistance,weathering resistance and UV resistance of the coatings were tested by acid and alkali tests,weathering performance tests and UV tests.The results of SEM characterization showed the presence of many large clusters and small particles of different shapes on the coating surface,indicating the presence of rough structures on the coating surface.And hydrophobic groups-CF₂ and-CH_n were also observed on the Fourier spectra,indicating the presence of low surface energy groups on the coating surface.These results explain the presence of hydrophobic properties of the coatings.7 months of outdoor tests,60 h immersion in p H=1 and p H=14 solutions,and 60 days of UV light exposure,it still has good hydrophobic properties.The above test results prove that the coating has good acid and alkali resistance,weathering resistance and UV resistance.（3）In addition,the wear resistance,photothermal performance and anti-icing performance of the MWCNTs/SiO₂/PDMS/PVDF superhydrophobic coating were verified.The hydrophobic coating maintained good superhydrophobic performance after approximately 80 wear cycles on360 grit sandpaper.Less than 5%of the coating was removed in the adhesion test.According to GB/T9286 standard,the adhesion level of the coating can be categorized as level 1.The absorption of light by the coating is basically higher than 90%in the wavelength range of 250-2500 nm.The onset of freezing and complete freezing of water droplets on the surface of the hydrophobic coating is delayed by more than a factor of two compared to the bare aluminum substrate under no-light conditions.And at an irradiation intensity of 0.2 Sun At an irradiation intensity of 0.2 Sun,the photothermal conversion performance of the coating not only prevents the freezing of 100μL of water droplets,but also rapidly melts the completely frozen ice crystals.Thus,the hydrophobic coating can effectively utilize its photothermal properties for anti-icing and ice melting even at low temperatures and under low light irradiation conditions.The results demonstrate the excellent anti-icing performance of the coating.