Dynamics of tetrahydrofuran as minority component in a mixture with poly(2-(dimethylamino)ethyl methacrylate): A neutron scattering and dielectric spectroscopy investigation

Goracci, G.; Lohstroh, W.; Alegría, A.; Arbe, A.; Colmenero, J.; Su, Y.

doi:10.1063/1.4929906

Journal Article

FZJ-2016-00387

Dynamics of tetrahydrofuran as minority component in a mixture with poly(2-(dimethylamino)ethyl methacrylate): A neutron scattering and dielectric spectroscopy investigation

Goracci, G. (Corresponding author) ; Arbe, A. ; Alegría, A. ; Lohstroh, W. ; Su, Y.FZJ* ; Colmenero, J.

2015
American Institute of Physics Melville, NY

The journal of chemical physics 143(9), 094505 - (2015) [10.1063/1.4929906]

This record in other databases:

Please use a persistent id in citations: http://hdl.handle.net/2128/9727 doi:10.1063/1.4929906

Abstract: We have investigated a mixture of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) and tetrahydrofuran (THF) (70 wt. % PDMAEMA/30 wt. % THF) by combining dielectric spectroscopy and quasielastic neutron scattering (QENS) on a labelled sample, focusing on the dynamics of the THF molecules. Two independent processes have been identified. The “fast” one has been qualified as due to an internal motion of the THF ring leading to hydrogen displacements of about 3 Å with rather broadly distributed activation energies. The “slow” process is characterized by an Arrhenius-like temperature dependence of the characteristic time which persists over more than 9 orders of magnitude in time. The QENS results evidence the confined nature of this process, determining a size of about 8 Å for the volume within which THF hydrogens’ motions are restricted. In a complementary way, we have also investigated the structural features of the sample. This study suggests that THF molecules are well dispersed among side-groups nano-domains in the polymer matrix, ruling out a significant presence of clusters of solvent. Such a good dispersion, together with a rich mobility of the local environment, would prevent cooperativity effects to develop for the structural relaxation of solvent molecules, frustrating thereby the emergence of Vogel-Fulcher-like behavior, at least in the whole temperature interval investigated.

Keyword(s): Polymers, Soft Nano Particles and Proteins (1st) ; Key Technologies (1st) ; Soft Condensed Matter (2nd)

Classification: