Constellation, le dépôt institutionnel de l'Université du Québec à Chicoutimi

Résumé

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.