Physical Chemistry seminar: Benedetta Rosi

A Physical Chemistry seminar by Dr. Benedetta Rosi, European Spallation Source (ESS), Lund

When: 23 March, 14:15-15:00

Where: Lecturehall KC:M

Title: Title: Investigations on the segmental dynamics of polymers in permanent and transient networks by neutron spectroscopy methods

Abstract: Viscoelastic and transport properties of polymers have both theoretical and applicative interest. Understanding such dynamic properties at the molecular level is desired, however, the occurrence of multiple processes on different time and length scales makes it a challenging task, especially for complex polymeric systems (e.g. transient and permanent networks). For this purpose, neutron scattering techniques are an ideal method as they give simultaneous access to the time and space evolution of the polymer segmental dynamics.

Applications of neutron spectroscopy to investigate dynamics of polymers in permanent and transient networks will be presented for two recent cases. The first case is that of a chemically crosslinked rubber, where the combination of different neutron spectroscopy methods (time-of-flight, backscattering, and spin echo) allows to separate scattering contributions describing self- and collective motions in the rubber.

The second case is that of semi-permanent polymer networks of grafted chains, where the effect of grafting and crosslinking can be treated as a modification of the well-known Zimm model describing polymer segmental dynamics in solution.