Anticorrosion and barrier properties appraisal of poly(dimethylsiloxane)–ZnO nanocoating transition from superhydrophobic to hydrophobic state / Innocent O. Arukalam in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 16, N° 4 (07/2019)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 16, N° 4 (07/2019) . - p. 1077-1088 Titre : Anticorrosion and barrier properties appraisal of poly(dimethylsiloxane)–ZnO nanocoating transition from superhydrophobic to hydrophobic state Type de document : texte imprimé Auteurs : Innocent O. Arukalam, Auteur ; Ying Li, Auteur Année de publication : 2019 Article en page(s) : p. 1077-1088 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Anticorrosifs Anticorrosion Hydrophobie Matériaux -- Propriétés barrières Mouillabilité Oxyde de zinc Revêtements protecteurs Test d'immersion Index. décimale : 667.9 Revêtements et enduits Résumé : The anticorrosion and barrier properties of poly(dimethylsiloxane) (PDMS)–ZnO nanocoating transition from superhydrophobic to hydrophobic state have been evaluated. The main objective was to appraise the durability performance of anticorrosion and barrier properties of the pristine superhydrophobic coating and its hydrophobic state after long-term exposure to marine water. Thus, water wettability, surface features, and corrosion resistance, as well as barrier performance of the 1H, 1H, 2H, 2H-perfluorodecyltrichlorosilane-modified PDMS–ZnO coating were evaluated after 15 cycles (1 h to 60 days) of immersion in 3.5 wt.% NaCl solution. The evaluations were made by use of surface analytical, physicochemical, and electrochemical techniques. The results show that the coating transformed from superhydrophobic state (after 1 h) to hydrophobic state (after 60 days). The transition was due to effect of corrosiveness of the salty water and disappearance of the surface air layer with consequent reduction in the surface roughness and increase in the porosity of the coating. Correspondingly, the value of the impedance modulus decreased from 4.257 × 109 Ω cm2 (after 1 h) to 7.175 × 108 Ω cm2 (after 60 days). The trend of coating film (Rcf) and charge transfer (Rct) resistances with immersion time was found to be somewhat stable after 40-day immersion time. The observed high values of impedance modulus (|Z|f=0.01 Hz), Rcf and Rct after 60 days of immersion clearly demonstrate that the anticorrosion property and barrier performance of the transformed hydrophobic PDMS–ZnO coating were good. Note de contenu : - Wettability results of the coating - Results of surface microstructure and roughness of the coating - Chemical composition of the superhydrophobic PDMS-ZnO nanocoating - Electrochemical impedance spectroscopy (EIS) results - Effect of wetting and immersion time on the anticorrosion behavior of the coating DOI : 10.1007/s11998-018-00182-2 En ligne : https://link.springer.com/content/pdf/10.1007%2Fs11998-018-00182-2.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=32863 [article]

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Epoxy-based smart coating with self-repairing polyurea-formaldehyde microcapsules for anticorrosion protection of aluminum alloy AA2024 / Chigoziri N. Njoku in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH, Vol. 17, N° 3 (05-06/2020)  

[article]  inJOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 17, N° 3 (05-06/2020) . - p. 797–813 Titre : Epoxy-based smart coating with self-repairing polyurea-formaldehyde microcapsules for anticorrosion protection of aluminum alloy AA2024 Type de document : texte imprimé Auteurs : Chigoziri N. Njoku, Auteur ; Weichen Bai, Auteur ; Innocent O. Arukalam, Auteur ; Lihui Yang, Auteur ; Baorong Hou, Auteur ; Demian I. Njoku, Auteur ; Li Ying, Auteur Année de publication : 2020 Article en page(s) : p. 797–813 Note générale : Bibliogr. Langues : Américain (ame) Catégories : Aluminium -- Alliages Anticorrosifs Anticorrosion Copolymère urée formaldéhyde Epoxydes Métaux -- Revêtements protecteurs Microcapsules Revêtement autoréparant Revêtement autoréparant:Peinture autoréparante Revêtements organiques Index. décimale : 667.9 Revêtements et enduits Résumé : Self-reparable microcapsules which can repair microcracks in the coating matrix and effectively inhibit the corrosion at the substrate/coating interface during service have been evaluated. The main objective was to fabricate an innovative pH-responsive permeability-switching polyurea-formaldehyde (PUF)-based microcapsule laden with 8-hydroxyquinoline (8-HQ) as the core material for the production of smart epoxy coating for the long-term protection of Al alloys. Combined improved barrier, active, and self-repairing properties indicating sort of triple-action corrosion mitigating ability of the modified epoxy-based smart coating was demonstrated by electrochemical impedance spectroscopy and scanning electron microscopy. The results indicate that the self-repairing action occurs via two mechanisms: firstly, by the initiation of chain mobility at the modified coating defects on heat treatment. Secondly, by the crosslinking of the swelled hydrogel present in the PUF shell wall via the various polymer–polymer interactions. The active corrosion protection was due to the (smart) pH response–release ability of the encapsulated inhibitor (8-HQ) with an increase in corrosion degree. Meanwhile, the even dispersal of the fabricated microcapsule with its intrinsic rough surface in the epoxy coating matrix contributed to the improved barrier and adhesive properties. Note de contenu : - MATERIALS AND METHODS : Materials - Methods - RESULTS AND DISCUSSION : Microcapsule morphology - Loading amount of 8-HQ in PUF microcapsules - Chemical content of the microcapsule - Release profiles of loaded inhibitor - Barrier properties of the unscratched coating - Evaluation of the combined active and self-repairing ability of the coating - Physical performance assessments DOI : https://doi.org/10.1007/s11998-020-00334-3 En ligne : https://link.springer.com/content/pdf/10.1007/s11998-020-00334-3.pdf Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34109 [article]

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