Effect of Confinement and Molecular Architecture on Interfacial Dynamics

The dynamics of polyester polyols in the bulk, under confinement when the polymers are intercalated within the galleries of a hydrophilic clay and close to the inorganic surfaces is investigated utilizing Dielectric Relaxation Spectroscopy (DRS). A series of linear biobased polyesters with hydroxyl end groups were utilized in the bulk and in nanohybrids and the results were compared with the case of hyperbranched polymers of similar chemistry but non-linear architecture. A broad range of temperatures below and above the bulk polymer glass transition temperature, T-g, was investigated covering both the regimes of beta-like local processes and segmental (alpha-process) dynamics. The polymer dynamics observed in all the nanocomposites are quite different compared to the bulk due to the different interactions whereas differences are seen due to the architecture as well. Moreover, non-standard local dielectric spectroscopy has been used to investigate the nanocomposites dynamics at the local scale: polymer relaxation has been investigated in the same material both close and far from the MMT surfaces. The comparison of the results from the two techniques allowed the understanding, in more detail, of the influence of the complex interfacial interactions on the relaxation dynamics.