Highly Transparent and Durable Superhydrophobic Hybrid Nanoporous Coatings Fabricated from Polysiloxane

Abstract

Highly transparent and durable superhydrophobic hybrid nanoporous coatings with different surface roughnesses were fabricated via a simple solidification-induced phase-separation method using a liquid polysiloxane (PSO) containing SiH and SiCH═CH2 groups as precursors and methyl-terminated poly(dimethylsiloxane)s (PDMS) as porogens. Owing to the existence of SiCHn units, the hybrid material is intrinsically hydrophobic without modification with expensive fluorinated reagents. The roughness of the coating can be easily controlled at the nanometer scale by changing the viscosity of PDMS to achieve both superhydrophobicity and high transparency. The influence of surface roughness on the transparency and hydrophobicity of the coatings was investigated. The enhancement from hydrophobic to superhydrophobic with increasing surface roughness can be explained by the transition from the Wenzel state to the Cassie state. The optimum performance coating has an average transmittance higher than 85% in the visible-light range (400-780 nm), a water contact angle of 155°, and a slide angle lower than 1°. The coatings also exhibit good thermal and mechanical stability and durable superhydrophobicity, which paves the way for real applications of highly transparent superhydrophobic coatings.

Fifty Years of Hydrosilylation in Polymer Science: A Review of Current Trends of Low-Cost Transition-Metal and Metal-Free Catalysts, Non-Thermally Triggered Hydrosilylation Reactions, and Industrial Applications

“…Due to its physical and mechanical properties, the siloxane-coating may possibly be applied in windshields, safety goggles, etc. Wang et al developed a method for synthesizing a highly transparent, durable, superhydrophobic, and nanoporous coating: As a precursor, they used a polysiloxane containing Si-H and vinyl-Si groups as well as a methyl-terminated PDMS as reagents ( Figure 46) [134]. Due to the Si-CH n groups abundantly present in the polymer, further fluorination to enhance the hydrophobicity is not required, enabling economically friendly production by phase-separation.…”

On the Durability and Wear Resistance of Transparent Superhydrophobic Coatings

“…One of the most challenging aspects of preparing non-wettable coatings is to maintain a good degree of transparency while retaining robust and scratch resistant self-cleaning and stain free characteristics [1][2][3]. Transparency and surface roughness are generally contradictory properties.…”

Superhydrophobic nanocoatings: from materials to fabrications and to applications

“…Because of this advantage, Si/SiO 2 based material received a lot of attention in 5 this research field. Xu et al 233 successfully fabricated highly transparent and durable superhydrophobic hybrid nanoporous coatings (Fig. 15g) using a liquid polysiloxane (PSO) containing SiH and SiCH=CH 2 groups as precursors and methyl-terminated poly(dimethylsiloxane)s (PDMS) as porogens via a simple 10 solidification-induced phaseseparation method.…”