Enamel Coatings and Surface (Super) Hydrophobicity

Vitreous enamel is hydrophilic due to its oxide components being affine to water, and there is little research on the hydrophobicity of enamel coatings. The Thesis introduces new knowledge on hydrophobic enamel coatings and significant contributions to the non-wettability concept through various solutions to hydrophobize enamel coatings. Experimental methodologies are based on a combination of surface roughening and silane treatment. The former increases roughness and the latter imparts a low surface energy to produce (super) hydrophobicity. The distinct inner microstructure of enamel was readily exposed by appropriate acid etching. After surface silanization, the microstructures improved the static hydrophobicity of coatings to a contact angle of 134o. The etched microscale structure contributed to mechanical durability against an abrasive cloth, while fluoroalkyl silane reagents provided a thermal stability of the enamel’s hydrophobic properties at an elevated temperature (400oC). Hydrophobic enamel coatings produced a water condensation in a dropwise manner which indicates qualitatively the enhanced surficial heat transfer for heat exchanger applications.