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Effects of varying the preparation conditions on the dielectric constant of mixed metal oxide films derived from layered double hydroxide precursor films / Xiaoxiao Guo in Industrial & engineering chemistry research, Vol. 48 N° 24 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10864–10869 Titre : Effects of varying the preparation conditions on the dielectric constant of mixed metal oxide films derived from layered double hydroxide precursor films Type de document : texte imprimé Auteurs : Xiaoxiao Guo, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur Année de publication : 2010 Article en page(s) : pp. 10864–10869 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Effects--Varying--Preparation--Conditions--Dielectric--Constant--Mixed--Metal--Oxide--Films--Derived--Layered--Double--Hydroxide--Precursor  Films Résumé : Magnesium/aluminum layered double hydroxide (LDH) films have been prepared in situ by means of urea hydrolysis using aluminum metal as both the substrate and sole source of aluminum. Scanning electron microscopy (SEM) images showed that the LDH crystallites are almost perpendicular to the substrate and interlaced with each other forming a network of vacant pockets. The film showed outstanding mechanical strength and high adhesion with the substrate. After being calcined at 500 °C, MgAl mixed metal oxide (MMO) films were obtained which retained the morphology of the precursor films. The values of dielectric constant (k) of the MgAl-MMO films were measured and showed low values in the range 2.0−4.7 arising from the low density of the interlaced structure. The effect of varying the preparation conditions of the LDH precursor films on the microstructure and k-value of the corresponding MMO films was investigated by varying the metal ion concentration, crystallization time, and crystallization temperature. The MMO films became more compact with increasing metal ion concentration and crystallization time, which resulted in increased k-values. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900671b [article] Effects of varying the preparation conditions on the dielectric constant of mixed metal oxide films derived from layered double hydroxide precursor films [texte imprimé] / Xiaoxiao Guo, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur . - 2010 . - pp. 10864–10869. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10864–10869 Mots-clés : Effects--Varying--Preparation--Conditions--Dielectric--Constant--Mixed--Metal--Oxide--Films--Derived--Layered--Double--Hydroxide--Precursor  Films Résumé : Magnesium/aluminum layered double hydroxide (LDH) films have been prepared in situ by means of urea hydrolysis using aluminum metal as both the substrate and sole source of aluminum. Scanning electron microscopy (SEM) images showed that the LDH crystallites are almost perpendicular to the substrate and interlaced with each other forming a network of vacant pockets. The film showed outstanding mechanical strength and high adhesion with the substrate. After being calcined at 500 °C, MgAl mixed metal oxide (MMO) films were obtained which retained the morphology of the precursor films. The values of dielectric constant (k) of the MgAl-MMO films were measured and showed low values in the range 2.0−4.7 arising from the low density of the interlaced structure. The effect of varying the preparation conditions of the LDH precursor films on the microstructure and k-value of the corresponding MMO films was investigated by varying the metal ion concentration, crystallization time, and crystallization temperature. The MMO films became more compact with increasing metal ion concentration and crystallization time, which resulted in increased k-values. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900671b

Effects of varying the preparation conditions on the dielectric constant of mixed metal oxide films derived from layered double hydroxide precursor films / Xiaoxiao Guo in Industrial & engineering chemistry research, Vol. 48 N° 24 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10864–10869 Titre : Effects of varying the preparation conditions on the dielectric constant of mixed metal oxide films derived from layered double hydroxide precursor films Type de document : texte imprimé Auteurs : Xiaoxiao Guo, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur Année de publication : 2010 Article en page(s) : pp. 10864–10869 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Layered  double  hydroxide  films  Scanning  electron  microscopy  images Résumé : Magnesium/aluminum layered double hydroxide (LDH) films have been prepared in situ by means of urea hydrolysis using aluminum metal as both the substrate and sole source of aluminum. Scanning electron microscopy (SEM) images showed that the LDH crystallites are almost perpendicular to the substrate and interlaced with each other forming a network of vacant pockets. The film showed outstanding mechanical strength and high adhesion with the substrate. After being calcined at 500 °C, MgAl mixed metal oxide (MMO) films were obtained which retained the morphology of the precursor films. The values of dielectric constant (k) of the MgAl-MMO films were measured and showed low values in the range 2.0−4.7 arising from the low density of the interlaced structure. The effect of varying the preparation conditions of the LDH precursor films on the microstructure and k-value of the corresponding MMO films was investigated by varying the metal ion concentration, crystallization time, and crystallization temperature. The MMO films became more compact with increasing metal ion concentration and crystallization time, which resulted in increased k-values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900671b [article] Effects of varying the preparation conditions on the dielectric constant of mixed metal oxide films derived from layered double hydroxide precursor films [texte imprimé] / Xiaoxiao Guo, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur . - 2010 . - pp. 10864–10869. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 24 (Décembre 2009) . - pp. 10864–10869 Mots-clés : Layered  double  hydroxide  films  Scanning  electron  microscopy  images Résumé : Magnesium/aluminum layered double hydroxide (LDH) films have been prepared in situ by means of urea hydrolysis using aluminum metal as both the substrate and sole source of aluminum. Scanning electron microscopy (SEM) images showed that the LDH crystallites are almost perpendicular to the substrate and interlaced with each other forming a network of vacant pockets. The film showed outstanding mechanical strength and high adhesion with the substrate. After being calcined at 500 °C, MgAl mixed metal oxide (MMO) films were obtained which retained the morphology of the precursor films. The values of dielectric constant (k) of the MgAl-MMO films were measured and showed low values in the range 2.0−4.7 arising from the low density of the interlaced structure. The effect of varying the preparation conditions of the LDH precursor films on the microstructure and k-value of the corresponding MMO films was investigated by varying the metal ion concentration, crystallization time, and crystallization temperature. The MMO films became more compact with increasing metal ion concentration and crystallization time, which resulted in increased k-values. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900671b

Facile fabrication and wettability of nestlike microstructure maintained mixed metal oxides films from layered double hydroxide films precursors / Hongyun Chen in Industrial & engineering chemistry research, Vol. 47 N°17 (Septembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 N°17 (Septembre 2008) . - p. 6607–6611 Titre : Facile fabrication and wettability of nestlike microstructure maintained mixed metal oxides films from layered double hydroxide films precursors Type de document : texte imprimé Auteurs : Hongyun Chen, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur Année de publication : 2008 Article en page(s) : p. 6607–6611 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Mixed  metal  oxide  films  Nestlike  microstructure  LDH  film  precursors  Scanning  electron  microscopy Résumé : Mixed metal oxide (MMO) films containing Ni2+ and Al3+ have been fabricated by a simple process involving calcination of layered double hydroxide (LDH) film precursors at 300−600 °C for 4 h in air. Scanning electron microscopy (SEM) reveals that the resulting Ni/Al−O thin films maintain the original nestlike morphology of the precursor films without any deformation of the microstructure during the thermal decomposition process. After surface treatment with an aqueous solution of sodium laurate, the wettability of the NiAl-LDH and Ni/Al−O thin film surfaces changes from hydrophilic to hydrophobic. Moreover, whereas the NiAl-LDH film exhibits a low adhesion for water (Cassie−Baxter behavior) after surface modification, the Ni/Al−O films exhibit a high adhesion for water (Wenzel behavior). A possible explanation for this phenomenon has been suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800388w [article] Facile fabrication and wettability of nestlike microstructure maintained mixed metal oxides films from layered double hydroxide films precursors [texte imprimé] / Hongyun Chen, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur . - 2008 . - p. 6607–6611. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 N°17 (Septembre 2008) . - p. 6607–6611 Mots-clés : Mixed  metal  oxide  films  Nestlike  microstructure  LDH  film  precursors  Scanning  electron  microscopy Résumé : Mixed metal oxide (MMO) films containing Ni2+ and Al3+ have been fabricated by a simple process involving calcination of layered double hydroxide (LDH) film precursors at 300−600 °C for 4 h in air. Scanning electron microscopy (SEM) reveals that the resulting Ni/Al−O thin films maintain the original nestlike morphology of the precursor films without any deformation of the microstructure during the thermal decomposition process. After surface treatment with an aqueous solution of sodium laurate, the wettability of the NiAl-LDH and Ni/Al−O thin film surfaces changes from hydrophilic to hydrophobic. Moreover, whereas the NiAl-LDH film exhibits a low adhesion for water (Cassie−Baxter behavior) after surface modification, the Ni/Al−O films exhibit a high adhesion for water (Wenzel behavior). A possible explanation for this phenomenon has been suggested. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800388w

Preparation of layered double hydroxide microspheres by spray drying / Yanchang Wang in Industrial & engineering chemistry research, Vol. 47 n°15 (Août 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5746–5750 Titre : Preparation of layered double hydroxide microspheres by spray drying Type de document : texte imprimé Auteurs : Yanchang Wang, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur ; Xiaoying Wang, Auteur Année de publication : 2008 Article en page(s) : p. 5746–5750 Note générale : Bibliogr. p. 5749-5750 Langues : Anglais (eng) Mots-clés : Layered  double  hydroxide  materials;  Separate  nucleation;  Spray  drying Résumé : In order to fully exploit their attractive properties in actual practical applications, layered double hydroxide (LDH) materials should be fabricated into macroscopic form. A magnesium−aluminum layered double hydroxide (MgAl-LDH) containing interlayer carbonate anions has been obtained using a synthesis route involving separate nucleation and aging steps, and microspheres of the material formed in a subsequent spray drying process. The resulting products are composed of nanosized LDH particles aggregated into solid microspheres with a diameter of 10-50 μm, a sphericity of 0.84, modal pore access diameter of 87.9 nm, surface area of 43 m2/g, and total pore volume of 1.29 cm3/g. The presence of an accessible diffusion pathway in the macropore domain of the LDH microspheres offers the possibility of enhanced performances in a wide range of applications. Furthermore, the spherical morphology of the materials was retained when the LDHs were converted into solid base catalysts by calcination and subsequent rehydration, indicating the robust nature of the macroscopic particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800146m [article] Preparation of layered double hydroxide microspheres by spray drying [texte imprimé] / Yanchang Wang, Auteur ; Fazhi Zhang, Auteur ; Sailong Xu, Auteur ; Xiaoying Wang, Auteur . - 2008 . - p. 5746–5750. Bibliogr. p. 5749-5750 Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°15 (Août 2008) . - p. 5746–5750 Mots-clés : Layered  double  hydroxide  materials;  Separate  nucleation;  Spray  drying Résumé : In order to fully exploit their attractive properties in actual practical applications, layered double hydroxide (LDH) materials should be fabricated into macroscopic form. A magnesium−aluminum layered double hydroxide (MgAl-LDH) containing interlayer carbonate anions has been obtained using a synthesis route involving separate nucleation and aging steps, and microspheres of the material formed in a subsequent spray drying process. The resulting products are composed of nanosized LDH particles aggregated into solid microspheres with a diameter of 10-50 μm, a sphericity of 0.84, modal pore access diameter of 87.9 nm, surface area of 43 m2/g, and total pore volume of 1.29 cm3/g. The presence of an accessible diffusion pathway in the macropore domain of the LDH microspheres offers the possibility of enhanced performances in a wide range of applications. Furthermore, the spherical morphology of the materials was retained when the LDHs were converted into solid base catalysts by calcination and subsequent rehydration, indicating the robust nature of the macroscopic particles. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800146m