## 3 Results and Discussion  
The molecular bonding of the fluorinated species as well as the silica bonds on surfaces coated with varying numbers of layers of the fluorine-functionalized silica nanoparticles were investigated with IRRAS spectral analyses. The Figure 1(A) shows the IRRAS spectra of the fluorinated silica nanoparticles spin coated aluminum substrates in one and nine layers. When one and nine layers are spin coated on the substrate, several peaks appear. The peak at 1,100 cm\({}^{-1}\) is due to the asymmetric stretching vibration of Si-O-Si bonds in the silica nanoparticles in the thin films [31; 32; 33; 34]. Another small peak appearing at around 800 cm\({}^{-1}\) is associated with the bending mode of Si-O-Si bonds. Also, the peak at 480 cm\({}^{-1}\) is associated with Si-O-Si bond for the rocking vibration [35]. This particular peak shows clearly an increase in intensity with an increase in the number of layers, proving an increase of the concentration of nanoparticles on the Al surface. Infrared analysis of the surface shows a peak around 945 cm\({}^{-1}\) which is attributed to silicon hydroxide (Si-OH) bonds present on unfunctionnalized silica nanoparticles [6]. Other interesting peaks are those present in the FAS17 molecules. At the beginning of the molecules, hydro-carbon bonds are present. A reasonably broad peak around 900 cm\({}^{-1}\) is assigned to the C-H bonds. Continuing on the molecules, fluoro-carbon bonds are present. The existence of C-F bonds in the form of CF, CF\({}_{2}\) or CF\({}_{3}\) are also located at 610, 730, 960 and 1,250 cm\({}^{-1}\)[33, 34, 36, 37]. The most important peak appears at 1,145 cm\({}^{-1}\). This particular peak represents a Si-O-C bond which confirms that the FAS17 molecule is clearly attached to silica nanoparticles. The presence of additional new peaks arising from the fluorinated functional groups present in the films confirms that the nanoparticles of silica are functionalized by fluorine from the FAS17 molecules. Figure 1(B) shows on the top a representation of a silica nanoparticle covered with a thin film of FAS17. On the bottom of the figure, a molecular representation of the fluorinated nanoparticles is presented with their corresponding wavenumbers. We have previously reported that that the size of silica nanoparticles can be easily controlled through the concentration of catalyst [6, 24, 38, 39]. Figure 2 shows SEM images of spherically shaped fluorinated silica nanoparticles of diameter 119 \(\pm\) 12 nm deposited in three layers on aluminum substrates. The inset of Figure 2(A) shows the image of a water drop placed on this aluminum substrate surface showing a very high water contact angle of \(\sim\)152\({}^{\circ}\). It is clear from these images that this surface is composed of several micrometer sized clusters of these spherical nanoparticles presenting randomly distributed holes and cracks by which the clusters are separated. It can also be seen from the higher magnification image in Figure 2(B) that these spherical fluorinated silica nanoparticles are also randomly stacked in steps of layers presenting different depths. Such an arrangement of randomly stacked spherical nanoparticles in clusters separated by cracks and holes provides the surface a rough micro-nanopattern. [PERSON] _et al._[38] obtained 110 \(\pm\) 20 nm silica  
Figure 1: **(A)** Transform Infrared spectroscopy (IRRAS) spectra of fluorinated silica nanoparticles coated aluminum surfaces as a function of the number of layers. **(B)** Schematic presentation of a silica nanoparticle functionalized with a thin layer of FAS17 (top) presented along with the corresponding wavenumbers on the IR spectra (bottom). nanoparticles using the Stober process at a NH\({}_{4}\)OH/TEOS molar ratio of 10, however, in our case, the size of the nanoparticles obtained under the same conditions are \(\sim\)10 nm larger (119 \(\pm\) 12 nm).