The AFM experiments were carried out in Intermittent contact working mode, using a EasyScan 2 model from Nanosurf® AG Switzerland, by means of a 10 × 10 μm high-resolution scanner with vertical range of 2 μm, z-axis 2-MPMDQ 0.027 nm and a X−Y linearity mean error of less than 0.6%. The images were scanned over the area of 2 × 2 μm. Sharp tips, NCLR from Nanosensors™, were employed for measurements, with a radius of curvature of less than 10 nm (typically 7 nm).
FT-IR spectra of the silica hybrid coatings deposited on polypropylene were measured using a Fourier Transformed Infrared spectrometer Tensor 37 (Bruker), recorded in ATR transmission mode. For all scans, the spectra were collected at 400–4000 cm−1, with a resolution of 4 cm−1.
3. Results and discussions
3.1. FT-IR studies
The properties of the final materials can be changed in the sol–gel process, by varying the experimental parameters involved, such as water to silica precursor molar ratio, solvent, temperature and catalysts ,  and .