Polarization phenomena on silicone

Practical experiments show that silicone adhesion on glass can be increased by eliminating the lowest molecular weight chains. The aim of this work is to precise the influence of short chain segments on silicone mobility. For this study, PolyDimethylSiloxane (PDMS) samples have been characterized by the Thermally Stimulated Current (TSC) spectrometry. In silicone, dielectric relaxations have two different origins: they are associated either with transitions or with polarization phenomena. At lower temperature, all the samples are characterized by the dielectric manifestation of the glass transition and, only after fractionating, with crystallization and melting phenomena. Around the room temperature, the polarization relaxation can be associated with adhesion mechanisms. Complementary dielectric, mechanical and thermal experiments have shown that these relaxation could be associated with surfacic polar group rotations around the Si-O and probably at the origin of silicone adhesive properties.