Developing core-shell silica nanoparticles to create multifunctional coating with excellent antireflection, enhanced antifogging and anticorrosion performances

How to fabricate a multifunctional coating with controllable ultralow refractive index (RI), high antifogging and anticorrosion performances by a facile method is still one of the great challenges. In this work, a simple and time-saving approach involving a microwave-assisted sol-sel process was developed to fabricate a novel core-shell structured silica nanoparticle sol by co-condensation of perfluorodecyltriethoxysilane (F-DTOS) and tetraethoxysilane (TEOS) and self-condensation of F-DTOS. Results suggest that both the co-condensations and self-condensations not only give a layer of low surface energy –C10H4F17 groups on the silica particles but also enlarge the hybrid silica particle size, providing more and larger voids to form the high porosity. After spinning the silica nanoparticles on the substrate, the obtained optical coating exhibits the controllable ultralow refractive index (RI) and outstanding transparency. The minimum RI and maximum transmittance of our developed coating is up to ~1.04 and ~100 %, respectively. Moreover, because of the high porosity and the presence of low surface energy –C10H4F17 groups in the coating, the coating has the high hydrophobicity (water contact angle ~108.8°), which not only makes it excellent antifogging performance but also affords it high-efficient anticorrosion property. After immersion in a 3.5 wt% NaCl solution for 7 days, the Rct value of the coating could be higher than 7.3 × 104 Ω cm2. It is believed that our developed method used to fabricate such multifunctional coating does not need any costly equipments, complex steps and time-consuming, making it well suited for industrial application.