Mechanical properties, icephobicity, and durability assessment of HT-PDMS nanocomposites: Effectiveness of sol-gel silica precipitation content

The main purpose of this research is to assess the effectiveness of precipitated nano-silica on mechanical properties and icephobicity of hydroxyl-terminated polydimethylsiloxane (HT-PDMS). It also tries to shed light on the correlation between mechanical characteristics and icephobicity of the abovementioned nanocomposites. In this regard, an icephobic coating was designed based on hydroxyl-terminated polydimethylsiloxane (HT-PDMS) elastomer through the sol-gel method with an emphasis on mechanical properties enhancement and durability. The quantity of precipitated nano-silica domains in HT-PDMS hybrid coatings was meticulously tailored by utilizing various ratios of tetraethyl orthosilicate (TEOS) and pre-hydrolyzed TEOS as silica domain precursors. It was established that using pre-hydrolyzed TEOS facilitated nano-silica precipitation and improved the coating's thermal stability and mechanical properties. Nano-silica precipitation was detected by thermogravimetric analysis (TGA) and confirmed by scanning electron microscopy (SEM). The abundance of nanosized silica particles precipitated by TEOS hydrolysis and condensation was < 5%, while > 20% in the nanocomposite sample precipitated by using pre-hydrolyzed TEOS. Tensile measurements indicated that greater silica precipitation enhanced tensile strength, elongation at break, and Young's modulus. The push-off test confirmed the very low shear ice adhesion strength (30-40 kPa) and the icephobic nature of the coatings. However, it was demonstrated that mechanical enhancement is correlated to ice adhesion strength up to 13.6% silica content, and icephobicity would be sacrificed at higher contents. Icing-deicing testing reveals that despite the initial ice adhesion strength increase by higher silica content, coatings present very better durability after repetitive cycles in greater silica value. [GRAPHICS]

Automated summary

The research aims to evaluate the effectiveness of precipitated nano-silica on the mechanical properties and icephobicity of HT-PDMS and explore the correlation between mechanical characteristics and icephobicity of the nanocomposites. An icephobic coating based on HT-PDMS elastomer was designed using the sol-gel method to enhance mechanical properties and durability. The amount of precipitated nano-silica in HT-PDMS hybrid coatings was controlled by using different ratios of TEOS and pre-hydrolyzed TEOS as silica precursors. It was found that utilizing pre-hydrolyzed TEOS improved the coating's thermal stability and mechanical properties.