The surface chemistry of metal fluoride nanocrystals
- Autores: Jordi Martínez Esaín
- Directores de la Tesis: Ramón Yáñez López (dir. tes.), Jordi Faraudo Gener (codir. tes.), Susagna Ricart Miró (codir. tes.)
- Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2018
- Idioma: español
- Tribunal Calificador de la Tesis: Daniel Maspoch Comamala (presid.), Anna Llordés Gil (secret.), María Ibáñez Sabaté (voc.)
- Programa de doctorado: Programa de Doctorado en Química por la Universidad Autónoma de Barcelona
- Materias:
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- Resumen
Starting from the synthesis of fifteen different types of inorganic nanocrystals, the general trends of metal fluoride nanocrystals have been successfully unraveled. Using the co-precipitation method, we reported the easy, fast and reproducible synthesis of LnF3 nanocrystals and the detailed mechanistic studies of different synthetic conditions.
Through the complete study of the surface chemistry, a new kind of ionic self-assembly in colloidal systems has been proposed. Using experimental techniques and molecular dynamics simulations, we postulated this self-assembly mechanism not only specific for the studied case but also applicable to other kind of systems. In addition, thermodynamically stable patchy nanocrystals have been also obtained using an easy, fast and reproducible method. The behaviour of these patchy nanocrystals has been investigated in detail using this dual approximation, from experimental techniques to all-atomistic molecular dynamics simulations. Our results revealed the spontaneous and selective attachment of cations and anions in their different exposed faces, as well as, selective solvent interactions.
Going one step further in patchy nanocrystals, we demonstrated that the different facets of the obtained nanocrystals can be modified selectively. Cations and anions can be removed from nanocrystal surface via the addition of a new molecule containing an amino group or a carboxylate respectively. Likewise, using a zwitterionic molecule, the homogenisation of the surface was possible releasing at same time cations and anions. Additionally, some growing process were carried out to enhance the obtained particles, allowing bigger hexagonal-faceted nanocrystals while trying to modify the organic stabilisers.
In addition, EGA-MS technique has been tested to simplify the complex pathway to full-characterise colloidal systems. We demonstrated that using a simple experimental technique, the full characterisation of a colloidal system is possible, comparing the results with our previous characterisations.
This thesis is mainly based on the mechanistic understanding of the synthesis and the final behaviour of the surface of LnF3 nanocrystals. In consequence, this knowledge will allow the control and manipulation of the bridge between synthesis and applications, currently called surface chemistry. Finally, some initial applications will be presented as different pathways emerged from the manipulation of the unravelled systems, being promising candidates for material science and medical fields.
