{'fraction_non_alphanumeric': 0.010777084515031198, 'fraction_numerical': 0.0017016449234259785, 'mean_word_length': 5.25531914893617, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Dielectric and mechanical properties of polymers at macro and nanoscale

The idea was first to understand the physical theories that describe the dynamics of linear polymers at the macroscopic scale. Rouse and the reptational tube theory describe the large scale dynamics of unentangled and entangled polymers respectively. Using Broadband Dielectric Spectroscopy (BDS) and rheology we have studied the different transition between these two regimes. Avoiding the segmental relaxation contribution and introducing a distribution in the molecular weight we have been able to perform a detailed comparison of the Rouse model with dielectric and rheological data. Effects of entanglement on dielectric spectra have been discussed. BDS and rheology are commonly used techniques to measure dielectric and mechanical properties but they do not have spatial resolution. Therefore the study of the local dynamics or heterogeneous system is always model dependant. We have developed EFM-based methods in order to study this local dynamics. Using the numerical simulation of the Equivalent Charge Method, the value of the static dielectric permittivity has been quantified from the measurement of the force gradient created by a Vdc potential between a tip and a grounded dielectric. This method allows a quantitative mapping of dielectric properties with a 40 nm spatial resolution and is therefore suitable for the study of nano-defined domains. The electrical phase shift in the 2 omega component of the force gradient created by Vac voltage is related with dielectric losses. We have developed a method to image the temperature-frequency dependence of the dielectric losses. These methods would allow the study of soft matter or biological phenomena at the local scale.