Enhanced superhydrophobic polyurethane nanocomposite coatings with nano-silica and PTFE: optimized self-cleaning and anti-icing properties

Polyurethane (PU) is a high-performance coating widely used in various environmental conditions, including humid and extreme temperatures. Despite extensive research into PU-based superhydrophobic coatings, their practical use is often limited by complex preparation methods and insufficient mechanical durability. This study introduces a simple, cost-effective method for creating superhydrophobic nanocomposite coatings with enhanced anti-icing properties. By applying a straightforward one-step thermal treatment, silica nanoparticles were hydrophobically modified. These nanoparticles, combined with PTFE powder, were incorporated into PU to form a superhydrophobic coating. The coating was analyzed using scanning electron microscopy to investigate its micro-nano-structure, atomic force microscopy and a surface profilometer to assess surface roughness, and surface free energy measurements to evaluate the effectiveness of the hydrophobic modification. The resulting coating achieved an apparent water contact angle of 152° ± 1°, representing a 116% increase compared to pure PU, and a sliding angle (SA) of 7° ± 1°. This represents a significant improvement over pure PU. It also demonstrated adequate self-cleaning and anti-icing properties. Anti-icing performance was assessed by measuring the freezing times of supercooled water droplets, demonstrating the coating's ability to delay ice formation. Additionally, the incorporation of paraffin oil was found to enhance ice inhibition. Additionally, cross-cut tape tests confirmed good adhesion. These findings confirmed that the prepared superhydrophobic nanocomposite coating shows significant potential for practical applications, offering enhanced durability, performance, and anti-icing capabilities.