In this article, thick (~15 pm) silicon-oxo-dominated nanocomposite coatings with high transparency were fabricated by incorporating 3-methacryloxypropyltrimethoxysilane (MPS)-modified silica alcosol into a moisture-curable polysiloxane oligomer and curing with the aid of 3-aminopropyllriehtoxysilane (APS).
Silica alcosol (30% solid content, particle size = 20 nm) was purchased from Zhangjiagang Churen New Materials Co.
Silica alcosol was added to a 50-mL round-bottom flask and magnetically stirred, and MPS was added drop-wise to the stirring vessel.
The MPS-modified silica alcosol was mixed with the as-obtained polysiloxane oligomer solution and sonicated for approximately 3 min.
Preliminary experiments showed that direct addition of silica alcosol to the as-obtained polysiloxane oligomer solution resulted in an opaque mixture.
The colloidal silica nanoparticles were centrifuged from the MPS-modified silica alcosol for FTIR characterization, as shown in Fig.
Thus, the incorporation of unmodified silica alcosol is not an efficient route to produce hard and tough coatings.
Samples fabricated with unmodified silica alcosol are shown for comparison.
A monotonous increase of the micromechanical properties is revealed only for coatings with S28 silica alcosol.
It was found that modification of silica alcosol with MPS was necessary to attain high transparency coatings.