ETD

• atomic force microscopy
• dielectric breakdown
• polymers

In this thesis, we introduce a new approach to measure the dielectric strength of polymeric materials and, more in particular, of ultra-thin polymer films. Conventional experimental techniques use macroscopic samples and electrodes. As a result, measurements obtained in this way are non-local, and only one measurement can be performed on a macroscopic sample.
Our approach is based on Atomic Force Microscopy. As a consequence, the resulting measurements are extremely local. This allows for performing multiple independent measurements on different areas of the same sample and for investigating the intrinsic dielectric breakdown of the material and not the one induced by its defects. Consequently, a much more significant statistical analysis can be performed.
We apply our technique to investigate the dielectric breakdown properties of three vinyl polymers: PS, P2VP, and P4VP. We focus on the temperature, thickness, and contact force dependence of the dielectric breakdown field.