Documents disponibles écrits par cet auteur

Influence of deposition time on layer-by-layer growth of clay-based thin films / You-Hao Yang in Industrial & engineering chemistry research, Vol. 49 N° 18 (Septembre 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8501–8509 Titre : Influence of deposition time on layer-by-layer growth of clay-based thin films Type de document : texte imprimé Auteurs : You-Hao Yang, Auteur ; Frank A. Malek, Auteur ; Jaime C. Grunlan, Auteur Année de publication : 2010 Article en page(s) : pp. 8501–8509 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Clay Résumé : The influence of deposition time on film growth of montmorillonite (MMT) or laponite (LAP) clay paired with branched polyethylenimine (BPEI) is studied here using layer-by-layer (LbL) assembly. Deposition times from 5 to 300 s in each ingredient were evaluated with respect to thickness, mass deposited, film structure, and oxygen barrier. Ellipsometry and quartz crystal microbalance show the BPEI/LAP system to be more dip-time dependent than the BPEI/MMT system because LAP platelets have a much smaller aspect ratio than MMT. Similar thickness is achieved for all recipes when only the BPEI deposition time is varied. Cross-sectional TEM images confirm thicker growth of BPEI/LAP in 300 s relative to 10 s. X-ray diffraction (XRD) suggests the gallery spacing between clay layers is insensitive to dip time, which is a key structural parameter linked to both mechanical and transport properties of these types of films. Additionally, oxygen transmission rates (OTR) are below the detection limit of commercial instrumentation (<0.005 cc/m2 day) in both 10 s/300 s and 300 s/300 s BPEI/MMT assemblies, suggesting similar defect-free structures in both cases. This study indicates that LbL assemblies could be produced more quickly, which is a key hurdle currently facing their commercial use. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100499x [article] Influence of deposition time on layer-by-layer growth of clay-based thin films [texte imprimé] / You-Hao Yang, Auteur ; Frank A. Malek, Auteur ; Jaime C. Grunlan, Auteur . - 2010 . - pp. 8501–8509. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 18 (Septembre 2010) . - pp. 8501–8509 Mots-clés : Clay Résumé : The influence of deposition time on film growth of montmorillonite (MMT) or laponite (LAP) clay paired with branched polyethylenimine (BPEI) is studied here using layer-by-layer (LbL) assembly. Deposition times from 5 to 300 s in each ingredient were evaluated with respect to thickness, mass deposited, film structure, and oxygen barrier. Ellipsometry and quartz crystal microbalance show the BPEI/LAP system to be more dip-time dependent than the BPEI/MMT system because LAP platelets have a much smaller aspect ratio than MMT. Similar thickness is achieved for all recipes when only the BPEI deposition time is varied. Cross-sectional TEM images confirm thicker growth of BPEI/LAP in 300 s relative to 10 s. X-ray diffraction (XRD) suggests the gallery spacing between clay layers is insensitive to dip time, which is a key structural parameter linked to both mechanical and transport properties of these types of films. Additionally, oxygen transmission rates (OTR) are below the detection limit of commercial instrumentation (<0.005 cc/m2 day) in both 10 s/300 s and 300 s/300 s BPEI/MMT assemblies, suggesting similar defect-free structures in both cases. This study indicates that LbL assemblies could be produced more quickly, which is a key hurdle currently facing their commercial use. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100499x