| Titre : |
Extended hydrophobicity and self-cleaning performance of waterborne PDMS/TiO2 nanocomposite coatings under accelerated laboratory and outdoor exposure testing |
| Type de document : |
texte imprimé |
| Auteurs : |
Fei Xu, Auteur ; Tao Wang, Auteur ; James Bohling ; Alvin M. Maurice ; Hong Yu Chen ; Limin Wu ; Shuxue Zhou |
| Année de publication : |
2018 |
| Article en page(s) : |
p. 1025-1034 |
| Note générale : |
Bibliogr. |
| Langues : |
Américain (ame) |
| Catégories : |
Applications extérieures
Dioxyde de titane
Essais accélérés (technologie)
Hydrophobie
Nanoparticules
PolydiméthylsiloxaneLe polydiméthylsiloxane —[O-Si(CH3)2]n—, ou poly(diméthylsiloxane) selon la nomenclature systématique, communément appelé PDMS ou diméthicone, est un polymère organominéral de la famille des siloxanes souvent présent dans les shampoings. On l'y ajoute pour augmenter le volume des cheveux mais il peut également aller boucher les pores du cuir chevelu et rendre les cheveux gras. C'est une des raisons pour lesquelles se laver les cheveux tous les jours est très déconseillé avec un shampooing contenant des silicones.
Il existe également de l'amodiméthicone, qui est un dérivé du diméthicone.
Le polydiméthylsiloxane est un additif alimentaire (E900), utilisé comme antimoussant dans les boissons (Coca-Cola BlāK).
La chaîne de poly(diméthylsiloxane) forme également la structure de base des huiles et des caoutchoucs silicones.
Revêtement auto-nettoyant
|
| Index. décimale : |
667.9 Revêtements et enduits |
| Résumé : |
It has been shown that incorporation of TiO2 nanoparticles into hydrophobic coatings can show self-cleaning performance. Accelerated laboratory testing indicated that the coats retain their hydrophobic nature for an extended time period. In this paper, hydrophobic polydimethylsiloxane (PDMS)/TiO2 nanocomposite coatings with a TiO2 content of 0–40% were fabricated by simple blending of a PDMS dispersion with an aqueous TiO2 nanoparticle dispersion. Their long-term hydrophobicity and self-cleaning performance were investigated both in laboratory and real-world outdoor testing. As expected, TiO2 nanoparticle-based coatings exhibited better self-cleaning relative to the TiO2-free PDMS control coating as measured by methylene blue degradation testing. Excellent long-term hydrophobicity was observed in accelerated weathering testing when they contained the appropriate levels of TiO2 nanoparticles (i.e., 0–30%). However, the same PDMS/TiO2 coatings did not show self-cleaning performance, and instead, exhibited improved dirt pickup resistance, in outdoor exposure testing. Sustained hydrophobicity was observed in outdoor exposure testing for the clear films except when TiO2 levels were at 40%. The hysteresis of water contact angle (HWCA) significantly increased for the PDMS control coating, and water beading was lost as the film surface picked up dirt. In contrast, the TiO2-based coatings with appropriate TiO2 levels maintained a relatively low HWCA after outdoor exposure and no water sheeting on rainy days was observed. This result demonstrates that while photocatalytic TiO2 nanoparticles can maintain coating hydrophobicity upon outdoor exposure, long-term self-cleaning performance in polluted environments has not yet been achieved with this type of coating under real-world conditions. |
| Note de contenu : |
- EXPERIMENTAL : Materials - Preparation of TiO2 nanoparticle dispersion - Preparation of hydrophobic PDMS/TiO2 nanocomposite coatings - Characterization
- RESULTS AND DISCUSSION : Preparation of the hydrophobic PDMS/TiO2 coatings - Performances of TiO2-based hydrophobic coatings in laboratory - Performances of TiO2-based hydrophobic coatings outdoors |
| DOI : |
10.1007/s11998-017-0037-0 |
| En ligne : |
https://link.springer.com/content/pdf/10.1007%2Fs11998-017-0037-0.pdf |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=31126 |
in JOURNAL OF COATINGS TECHNOLOGY AND RESEARCH > Vol. 15, N° 5 (09/2018) . - p. 1025-1034
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