Soutenance de Baptiste Ferrero
| When |
Jan 25, 2023
from 10:00 to 12:00 |
|---|---|
| Where | Salle des thèses |
| Contact Name | Baptiste Ferrero |
| Attendees |
Baptiste Ferrero |
| Add event to calendar |
vCal
iCal
|
The dispersion of metallic oxides within a polymer matrix is used to enhanced its dielectric properties while preserving its interesting mechanical properties. A better understanding of the interactions between the different materials of such a composite is nevertheless required in order to fully optimize the end product.
The aim of this PhD thesis was to create a system able to perform nanoscale characterisation of the dielectric response of a polymer-oxide composite by the mean of Atomic Force Microscopy (AFM). This method give us access to the microscopic dynamic of polymer chains in interactions with the particles. The system is highly precise due to the use of an interferometric monitoring of the deflection of the AFM cantilever and the multiple isolation systems shielding the measure from outside noises, including a Faraday cage, a semi-anechoic chamber. Additionally the measure is performed within a vacuum chamber under temperature control.
To characterize the precision and reliability of the interferometric measure system, the impact of optical imperfections have been extensively studied. An innovative calibration method to compensate these imperfections is offered. It improves the end linearity of the mesure in comparison to the traditionally used methods of correction. Finally, a proof of principle of our ability to perform dielectric measure is demonstrated upon a sample of PVdF-HFP composite mixed with BaTiO3 nanoparticles. It shows the potential of our method for the cartography of dielectric properties on the scale of these 50 nm diameter particles.