Porous Microcapsule-Based Regenerating Superhydrophobic Coating on 304L SS and Its Corrosion Properties

Autor: John Philip, R.P. George, S.C. Vanithakumari, T.P. Rasitha
Rok vydání: 2019
Předmět:
Zdroj: Journal of Materials Engineering and Performance. 28:7047-7057
ISSN: 1544-1024
1059-9495
DOI: 10.1007/s11665-019-04425-0
Popis: We report fabrication of a regenerating superhydrophobic coating on 304L stainless steels, with superior corrosion resistance, using porous microcapsules made of calcium hydroxide as a core and a polymeric shell consisting of ethyl cellulose and poly methyl methacrylate. The synthesized microcapsules are characterized using optical, atomic force and scanning electron microscopic techniques, x-ray diffraction, Fourier transform infrared spectroscopy and immersion tests. The diameter of porous and permeable microcapsules ranges from 2 to 20 μm. On immersion of the coated surface in sodium stearate solution, the calcium hydroxide from the core diffuses through the pores of microcapsules and forms nanocrystalline hydrophobic calcium stearate needles pointing outward that repel water molecules. The maximum water contact angle obtained was 155.7° ± 2.05°. The micro-nanoscale roughness of the surface was evident from the AFM measurement. The cross-hatch tape adhesion test confirmed the strong adherence of the superhydrophobic coating. On damage of the superhydrophobic coating, the regeneration is achieved by immersing it in sodium stearate solution for 6 h where a 10° increase in contact angle is observed. Electrochemical studies in 0.1 M NaCl showed significant decrease in the passive current density and a delayed pitting, confirming better corrosion resistance of the coating in chloride environment.
Databáze: OpenAIRE
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