Identification and metrological characterization of nanoparticles in complex matrix ; Identification et caractérisation métrologique des nanoparticules en matrices complexes

Since the 2000s, nanomaterials (NMs) have become part of our daily routine and are increasingly present on the worldwide market. These NMs are used in various sectors of activity such as construction, food, health, automotive and many others. Normative definitions and regulations have been established to control the NMs traceability throughout their life cycle. In Europe, regulatory requirements (labelling obligation if nano ingredients are used as additives for food, cosmetics or biocides) impose to the additives users to know if the substances should be considered as "nano" or not. A reliable metrology is therefore necessary for the nano-objects identification and characterization. However, this metrological characterization remains a challenge due to the numerous parameters to be considered in order to fully describe these nano-objects (size, size distribution, agglomeration/aggregation state, shape, specific surface area, chemical composition, surface chemistry and surface charge), which are listed in the ISO/TC 229 (PDTR 13014) standard. The thesis general context is the NMs characterization and more specifically dimensional characterization at the nanometric scale. The study focus on the Titanium dioxide (TiO2) (nano) particles which are ranked among the 5 most produced nanoparticulate substances (based on tonnage) in the world and used in many applications.The objective is to evaluate and compare measurands of several dimensional characterization techniques for nanoparticles and thus determine their constituent particle size. In this way, ensemble and integral techniques such as SAXS (small angle X-ray scattering), DLS (dynamic light scattering) and BET (Brunauer-Emmett-Teller) have been compared to the direct measurement technique, SEM (scanning electron microscopy).Emphasis is placed on the influence evaluation of several factors, namely, the size, the shape as well as the particles crystallinity and the complex matrix (set of elements in coexistence with the particles of interest), on the realized ...