Effect of processing process on the performance of hybrid sol-gel super-hydrophobic coatings.

The researchers studied the effects of the process on the dynamics and properties of the hybrid sol-gel ultra-hydrophobic coating.
a mixed ultra-hydrophobic sol-gel coating and applied it to a glass substrate. Low surface energy can be obtained using hydrophobic organic silane, while alkyl modified silicon dioxide nanoparticles (NPs) can form roughness

. However, these ultra-hydrophobic coatings (SHCs) are known to lack NP interface adhesion and limited interface adhesion to the lower substrate, which is easy to remove in harsh environments, as evidenced by this.
For research purposes, a hybrid SHC based on hydrophobic sol-gel and hydrophobic silica NPs was prepared with the aim of enhancing interface adhesion between silicon dioxide NP and sol-gel substates, as well as between sol-gel substates and glass substates.
dual-curing SHC has the highest mechanical and environmental durability
so three curing processes are studied: thermo cure, radiation curing and double curing. Dual curing SHC has the highest mechanical and environmental durability. It maintains 17 tape peels and 1000 hours of ultra-hydrophobic (SH) under accelerated weathering conditions. Failure analysis shows that due to interface free-based chemistry and due to shrinking chemistry, a strong interface bonding is formed between the sol-gel coating and the glass substrate between the alkylally modified silicon dioxide nanoparticles and the hybrid hydrophobic sol gel substrate.
addition, the dual-cured hybrid sol-gel shows a transparent SHC with a light transmission rate of more than 90%, a water contact angle (CA) of 160 degrees, and a corresponding sliding angle (SA) of 0 degrees. Morphological and roughness analysis shows a uniform, layered structure consisting of micron-scale and nano-scale roughs with Gaussian density distributions, such as lotus leaf surfaces. According to ATR-IR analysis, the dual curing process combines functional vinyl silane to form a chain polymerization mechanism of the sioxane network through radiation and fluosilane thermal shrinkation reactions. Therefore, only the chain or only the shrinking process results in partial crosslinking of the network and the low interface adhesion of the NP and sol-gel systems.
the study was published in March 2020 in volume 140 of Organic Coatings Progress.
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