Exfoliation of 2D mineral phases, their deposition in thin layers and applications ; Exfoliation de phases minérales 2D, leurs dépôts en couches minces et applications

This thesis is dedicated to the study of a selection of 2D materials formed by negatively charged layers, including phosphatoantimonic acid, bentonite and lamellar aluminophosphates. These materials are chosen for their chemical stability which gives them a wide range of applications. Their syntheses are performed according to known protocols. Their exfoliation in liquid phase allows the study of the structure of their sheets as well as their properties at the nanometric scale. In this thesis, we report the first exfoliation tests of lamellar aluminophosphates in green solvents. Bentonite is a clay that is exfoliated by contact with water. Like clays, phosphatoantimonic acid gives a colloidal suspension in water. The latter is characterized by an acid pH. The study of its neutralization by addition of alkaline bases allowed the discovery of a new behavior of these nanosheets. Our work shows that they can shift from the exfoliated state to a crystalline state. Being exfoliated, these materials are used to develop liquid compositions in the presence of surfactant molecules. The aim is to allow the realization of thin films of nanosheets by a new deposition method developed at CEA. The latter is based on the transfer of nanosheets confined in a water film stabilized by surfactants. The results presented include scanning electron microscopy (SEM) and atomic force microscopy (AFM) characterizations of the individual nanosheets and films deposed with this method. This approach allows to obtain deposits of variable and controllable thicknesses, ranging from monolayers to multilayers by adjusting the concentration of nanosheets. Moreover, this approach allows the transfer of thin nanosheet-based films on different types of surfaces, which allows them to be used for different purposes. This is illustrated by our first results for the functionalization of carbon nanotube based sensors as well as the formation of anti-graffiti protection layers. ; Cette thèse est dédiée à l'étude d'une sélection de matériaux 2D formés par ...