Study of polymers with various chemical structures and chain architectures by thermo-stimulated currents and broadband dielectric spectroscopy

In order to improve, in polymeric materials, the understanding of the nature of molecular mobility and the hierarchy of dipolar movements, we analyse the dipolar polarisation. This study is realised on model polymers with two types of architectures, linear and dendritic, to emphasise the part played by the chain structure. For this dielectric study, we use the dynamic dielectric spectroscopy, that allows us to sweep a wide frequency range (10^-2-10⁶ Hz), and the thermo-stimulated currents technique, that allows us to determine experimentally the fine structure of complex relaxations. We show that a type of polarisation (radiofrequency, low frequency and very low frequency polarisation) can be directly related to a kind of molecular mobility: localised and noncooperative motions, then more delocalised and cooperative motions and, finally, motions delocalised along the entire chain.