Document Type : Research Paper


1 Materials Engineering Department, University of Technology-Iraq, Alsina’a Street, P.O Box 10066 Baghdad, Iraq.

2 Department of Materials Engineering, University of Technology, P.O. Box 10066, Baghdad, Iraq


This works aims to investigate the influence of three different categories of silica, namely, precipitated silica, fumed silica and nanosilica prepared via sol-gel process, for hydrophobic application in this work. Nanosilica was characterised using scanning electron microscopy, Fourier transform infrared spectroscopy, particle size and zeta potential. Diluted silicone rubber (room-temperature vulcanising silicone) was also used as a matrix for these particles as (3/1) weight%; silicone rubber/silica. Cold spraying technique was applied to coat glass substrates. Fourier transform infrared analysis was applied to investigate the coating. SEM observation and particle size analysis established that the nanosize of silica is used with narrow-size distribution. Zeta potential analysis demonstrated the stability of nanoparticles at recorded average values of −41 to −50 mV. Wettability results showed that all types of silica incorporated into the silicone rubber present a hydrophobic surface. The maximum recorded value of contact angle was 146° for sol-gel-prepared silica/silicone rubber. The out findings indicated that these compounds are acceptable candidates for hydrophobic glass applications.


  • The sol-gel-prepared silica incorporated into the RTV matrix demonstrated the optimal hydrophobic surface at contact angle 146°.
  • Zeta potential analysis demonstrated the stability of nanoparticles at recorded average values of −41 to −50 mV.
  • Some XRD peak intensities of hydrophobic coating (RTV silicone rubber/silica) coated glass differed from the neat component (RTV or silica).
  • XRD differences between the neat materials and their corresponding composite demonstrate satisfactory incorporation and a cohesive layer that produced significant bonding between components.


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