Highly stable self-cleaning antireflection coatings from fluoropolymer brush grafted silica nanoparticles

Abstract

Self-cleaning antireflection coatings have potential applications in outdoor conditions and have been the subject of intense study. However, self-cleaning antireflection coatings are commonly prepared via grafting of small hydrophobic molecules, which are susceptible to detachment from the coatings due to hydrolysis, leading to considerable degradation of the self-cleaning functionality in practical applications. Here, we create fluoropolymer brush grafted silica antireflection coatings that demonstrate long-term self-cleaning performance. Fluoropolymer brush grafted silica nanoparticles were synthesized via surface initiated atom transfer radical polymerization and then coated on glass substrates to form antireflection coatings. The brush grafted coatings exhibited excellent transmission, with nearly 100% transmittance at a desired wavelength. The fluoropolymer brushes rendered the coatings hydrophobic, with water contact angle of 122°. Owing to their hydrophobicity, the brush grafted coatings exhibited excellent self-cleaning functionality. A notable advantage of the brush grafted coatings was their stable self-cleaning functionality. The brush grafted coatings remained their hydrophobicity after immersion in acidic solution, with water contact angle being constant at 122°, which were more stable than the small molecule modified hydrophobic coatings. This work opens a new avenue to create highly stable self-cleaning antireflection coatings that will find applications in harsh conditions.