Preparation And Properties Of Superhydrophobic F-SiO₂@PDMS Coatings

Superhydrophobic coatings have shown huge application potential in numerous fields owing to their special nonwettability.As a kind of common superhydrophobic coatings,nanocomposite superhydrophobic coatings contain nanomaterials?such as SiO₂,TiO₂,Al₂O₃ and ZnO,etc.?,which results in poor durability and limits their commercialization.To this end,we designed a highly flexible superhydrophobic F-SiO₂@PDMS coatings with improved durability,and carried out relevant application researches.The main contents and conclusions of this thesis were summarized as follows:?1?The superhydrophobic F-SiO₂@PDMS coatings were prepared through a two-step spraying method.The influence of F-SiO₂ content and particles size,as well as the precuring time of PDMS on the nonwettability of coatings was investigated.Under condition of spraying 0.88%F-SiO₂?20 nm?suspension on PDMS with precuring time of 10 min,we obtained the ideal F-SiO₂@PDMS superhydrophobic coatings having great bonding strength with SiO₂ nanoparticles.?2?The superhydrophobic F-SiO₂@PDMS coatings were endowed with fluctuant morphology and lower adhesion force of droplets,showing the excellent superhydrophobicity.Due to the immobilization of PDMS,the superhydrophobic F-SiO₂@PDMS coatings remained great water-repellency after 5cycles of mechanical abrasion.When the coatings were elongated to 83.3%,the free-standing superhydrophobic F-SiO₂@PDMS coatings still showed high superhydrophobicity.In addition,it was demonstrated that the superhydrophobic F-SiO₂@PDMS coatings diaplayed ideal self-cleaning and anti-fouling property,and drag-reduction performance.?3?The superhydrophobic F-SiO₂@PDMS coatings possessed the excellent corrosion resistance and adaptability for different pH liquids.The quality of aluminum sheets covered with the superhydrophobic F-SiO₂@PDMS coatings hardly changed after the acid immersion.Comparing with bare aluminum and PDMS coatings,superhydrophobic F-SiO₂@PDMS coatings had the lower corrosion current and higher corrosion voltage.Molecular dynamics simulation implied that the diffusion coefficient of corrosion particles in the coatings was very small,and the interaction between the particles and the coatings was so weak that the coatings could well resist the erosion of Cl^-ions.?4?Comparing with pure aluminium and PDMS coatings,the superhydrophobic F-SiO₂@PDMS coatings had better dynamic water repellency at low temperature,and the contact time of impact droplets was only 11.6 s under-10°C.The great icephobicity was another superiority of the superhydrophobic F-SiO₂@PDMS coatings,where the icing time could reach 276.2s?³.4 times and57.5 times higher than PDMS coatings and pure aluminum?.The ice adhesion strength on superhydrophobic F-SiO₂@PDMS coatings was only 26.3 kPa,which was 96.8%lower than that of pure aluminum.Finally,the anti-icing properties still retained high stability under the conditions of 30icing/deicing cycles,soaking and scouring of acid solution,and the ice adhesion strength was still less than 100 kPa.