Influence of silicon dioxide nanoparticles on hydrophobicity and transparency of polydimethylsiloxanes coatings hybridized with silicon dioxide nanoparticles

Dust deposition on outdoor glass and photovoltaic panels presents a significant challenge, often requiring active cleaning methods to maintain daylighting, efficiency, and aesthetics. Therefore, highly transparent and hydrophobic coatings that enable passive self-cleaning of these surfaces are highly desirable. Polydimethylsiloxanes (PDMS) coatings hybridized with silicon dioxide (SiO2) nanoparticles have emerged as a promising solution. However, systematic studies on how hydrophobicity and transparency depend on nanoparticle properties were rarely reported, hindering practical implementation. In this study, we systematically investigated the hydrophobicity and optical transparency of PDMS coatings hybridized with different contents of SiO2 nanoparticles with various diameters. SiO2 nanoparticles with varying diameters were synthesized using the sol-gel method, followed by the development of PDMS coatings hybridized with SiO2 nanoparticles via spin coating technology. It is demonstrated that the PDMS coatings with larger SiO2 nanoparticles exhibited larger contact angles at low nanoparticle contents. At higher contents, the contact angles remained nearly constant, while transmittance decreased significantly owing to light scattering. Additionally, PDMS coatings hybridized with SiO2 nanoparticles exhibited good mechanical stability and self-cleaning properties, indicating their potential in outdoor applications. These findings provide valuable insights into optimizing PDMS-SiO2 hybrid coatings, balancing hydrophobicity and transparency.