Multivariable analysis of electrodeposited silane based superhydrophobic coatings for corrosion protection of carbon steel

Evaluation of Structure, Heterogeneities, Thickness and Corrosion Protection of Electrodeposited Sol-Gel Superhydrophobic Coatings

“…As it can be seen, it presents high porosity and roughness in millimetric and micrometric scales, which can indeed entrap air, increasing surface hydrophobicity. It is worth noting that, even though the applied techniques cannot detect nanometric scales, its presence is also expected due to the water contact angle values superior to 157 o obtained by such film in previous work 15 , in agreement with the Cassie-Baxter model 16 . Furthermore, the analysis of Figure 3 points out that the deposit formation was given by the random agglomeration of particles slightly smaller than 5 µm.…”

“…However, one interesting fact, not yet reported, are preferential deposition regions, as shown in Table 1, which describes thickness values for the regions highlighted in Figure 2 by the letters A to L. Based on such results, it was possible to point out that the coating top region, marked by the letter A, B, and C, provided greater thicknesses than the bottom region. It is essential to highlight that the same trend could also be identified under different deposition conditions, such as those described in our previous work 15 . Despite that, the methodology presented great repeatability regarding the average thickness, with standard deviation among replicates equal to 2.70 µm.…”

“…This work complemented previously published results 15 , following its methodology for film formation, and analysed in detail the structure of the film and its heterogeneities, as well as their influence on the corrosion behaviour of carbon steel. Furthermore, the effect of the amount of TEOS and OTES added to the system while maintaining their molar ratio equal to 1, was evaluated considering the WCA, film thickness, corrosion protection, and film heterogeneities as response variables.…”

“…It is important to point out that NaNO 3 was employed in order to control the sol stability and conductivity, which, among other variables, are important factors for electrodeposition, as described in a previous work 15 .…”

“…Their methodology yielded thicker coatings (~20 µm), but similar WCA to the work from Wu et al 12 . In a previous work published by our research group 15 , 11 variables associated with sol-gel processing, electrodeposition, and film drying were evaluated to maximize WCA and impedance modulus in NaCl 3.5%wt. of superhydrophobic coatings produced by the combination of TEOS and octyltriethoxysilane (OTES).…”