Thermotropic and lyotropic liquid crystals for the formation of zinc oxide nanohybrids / Sarmenio Saliba  

Public ISBD Titre : Thermotropic and lyotropic liquid crystals for the formation of zinc oxide nanohybrids Type de document : texte imprimé Auteurs : Sarmenio Saliba, Auteur ; Jean Daniel Marty, Directeur de thèse ; Kahn, Myrtil, Directeur de thèse Année de publication : 2011 Langues : Anglais (eng) Tags : NANOPARTICLES  LIQUID CRYSTALS  ANISOTROPIC GROWTH  ZINC OXIDE Résumé : "The work presented in this manuscript describes the incorporation of inorganic materials inside organic hosts. Our ambition was to successfully hybridize ZnO nanostructures with liquid crystals. This was achieved using different strategies, the choice of which depended on the desired properties of the final material. The objective was not only the synthesis and stabilization of the nanoparticles within, but also their organization in the LC medium. One approach was the functionalization of preformed ZnO spherical nanoparticles by thermotropic LC ligands. This was made possible using a ligand exchange mechanism. Due to a dynamic equilibrium at the surface of ZnO NPs, the mesogenic molecules could exhibit order at the molecular level, giving rise to novel LC/NP hybrids with enhanced LC properties. The organization of NPs could also be induced by the use of lyotropic liquid crystals. In this case, the NPs were not simply doped into a LC material, but synthesized directly inside the lyotropic phases. The synthesis of ZnO was therefore confined to domains of defined size and shape which can directly control the organization of the nanostructures growing within. Apart from organization of NPs, our constant objective was the fabrication of anisotropic nanoobjects via LC-assisted synthesis. Thermotropic liquid crystals consisting of novel low molecular weight branched mesogens have proved to be remarkable templates for anisotropic growth of ZnO nanocrystals. This anisotropic growth was also found to be influenced by the size of the LC molecules as observed with the fabrication of ZnO inside LC polymers. This work has shown the possibility of integrating inorganic material in LCs providing that the two constituents are able to sufficiently interact with one another." Document : Thèse de doctorat Etablissement_delivrance : Université de Toulouse 3 Date_soutenance : 22/07/2011 Ecole_doctorale : Sciences de la matière (SdM) Domaine : Chimie macromoléculaire et supramoléculaire En ligne : http://thesesups.ups-tlse.fr/1598/ Thermotropic and lyotropic liquid crystals for the formation of zinc oxide nanohybrids [texte imprimé] / Sarmenio Saliba, Auteur ; Jean Daniel Marty, Directeur de thèse ; Kahn, Myrtil, Directeur de thèse . - 2011. Langues : Anglais (eng) Tags : NANOPARTICLES  LIQUID CRYSTALS  ANISOTROPIC GROWTH  ZINC OXIDE Résumé : "The work presented in this manuscript describes the incorporation of inorganic materials inside organic hosts. Our ambition was to successfully hybridize ZnO nanostructures with liquid crystals. This was achieved using different strategies, the choice of which depended on the desired properties of the final material. The objective was not only the synthesis and stabilization of the nanoparticles within, but also their organization in the LC medium. One approach was the functionalization of preformed ZnO spherical nanoparticles by thermotropic LC ligands. This was made possible using a ligand exchange mechanism. Due to a dynamic equilibrium at the surface of ZnO NPs, the mesogenic molecules could exhibit order at the molecular level, giving rise to novel LC/NP hybrids with enhanced LC properties. The organization of NPs could also be induced by the use of lyotropic liquid crystals. In this case, the NPs were not simply doped into a LC material, but synthesized directly inside the lyotropic phases. The synthesis of ZnO was therefore confined to domains of defined size and shape which can directly control the organization of the nanostructures growing within. Apart from organization of NPs, our constant objective was the fabrication of anisotropic nanoobjects via LC-assisted synthesis. Thermotropic liquid crystals consisting of novel low molecular weight branched mesogens have proved to be remarkable templates for anisotropic growth of ZnO nanocrystals. This anisotropic growth was also found to be influenced by the size of the LC molecules as observed with the fabrication of ZnO inside LC polymers. This work has shown the possibility of integrating inorganic material in LCs providing that the two constituents are able to sufficiently interact with one another." Document : Thèse de doctorat Etablissement_delivrance : Université de Toulouse 3 Date_soutenance : 22/07/2011 Ecole_doctorale : Sciences de la matière (SdM) Domaine : Chimie macromoléculaire et supramoléculaire En ligne : http://thesesups.ups-tlse.fr/1598/

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