Preparation of PTSLIPS coatings using polyurethane-based nanocomposite and investigation of their hydrophobicity and anti-icing properties

Abstract

Researchers have shown a keen interest in phase transformable lubricant-infused porous surfaces, given their commendable attributes, including hydrophobicity, high anti-icing properties, strength, durability in harsh conditions, and simple design. In this study, a straightforward methodology was employed to fabricate a cost-effective phase transformable slippery liquid-infused porous surfaces (PTSLIPS) coating using polyurethane (PU) and hydrophobic silica nanoparticles (SNPs). In this regard, hydrophobic SNPs were fabricated and modified through a cost-effective one-pot method. The prepared hydrophobic SNPs were characterized using FTIR, SEM, and XRD techniques. The results confirmed the successful synthesis of hydrophobic SNPs using the aforementioned method. The silanization method was utilized to diminish the surface energy of the resulting coating. The PU based nanocomposites containing different weight ratios of silica and tetraethyl orthosilicate (TEOS) were casted on glass and aluminum substrates. Subsequently, these coatings were immersed in coconut oil, a natural and eco-friendly lubricant, to establish a slippery surface. In order to phase transition of lubricant from liquid to solid, the coatings were placed in a freezer. According to the of SEM and AFM results, increasing the content of nanoparticles and TEOS in the coatings to 10 wt% improves the hydrophobicity of the coatings. Also, wettability experiments uncovered that the coating with 10 wt% modified SNPs and 10 wt% TEOS exhibited the most substantial static contact angle (141°) and dynamic angle (1.9°), rendering it the optimal choice. Notably, the presence of this coating delayed water icing time on surface by 6.26, 8.08, 4.99, and 7.67 times compared to glass and aluminum bare surfaces and pure polyurethane-coated glass and aluminum surfaces, respectively. Impressively, the coating demonstrated high stability after 10 icing/de-icing cycles and immersing 15 days in saturated salty and acidic rain solutions. It can be concluded that the prepared coating can be used on different substrates in various fields such as aerospace, maritime, and automobile industries because it has represented good potentials including high hydrophobicity, anti-icing ability, and good durability in harsh conditions.