TY  - JOUR
AU  - Goracci, Guido
AU  - Arbe, Arantxa
AU  - Alegría, Angel
AU  - García Sakai, Victoria
AU  - Rudić, Svemir
AU  - Schneider, Gerald J.
AU  - Lohstroh, Wiebke
AU  - Juranyi, Fanni
AU  - Colmenero, Juan
TI  - Influence of Solvent on Poly(2-(Dimethylamino)Ethyl Methacrylate) Dynamics in Polymer-Concentrated Mixtures: A Combined Neutron Scattering, Dielectric Spectroscopy, and Calorimetric Study
JO  - Macromolecules
VL  - 48
IS  - 18
SN  - 1520-5835
CY  - Washington, DC
PB  - Soc.
M1  - FZJ-2016-01404
SP  - 6724 - 6735
PY  - 2015
N1  - "final draft post referee" kann nicht beigebracht werden
AB  - We have investigated the dynamical processes—α-relaxation, local motions of the side-groups, and methyl group rotations—in poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) in the dry state and in mixtures (at 70 wt% polymer concentration) with tetrahydrofuran (THF) and water, to address the question as to how these polymer motions are affected by plasticizers interacting in different ways with the polymer. Differential scanning calorimetry, dielectric spectroscopy, and neutron scattering techniques on labeled samples (with deuterated solvents to isolate the signal of the polymer component) have been combined. The α-relaxation is drastically affected, with similar shifts of the glass-transition temperature for both solvents. Effects of compositional heterogeneities and reduction of the fragility are also observed. On the contrary, methyl-group dynamics are unaffected by the presence of solvent. Regarding side-group local motions (β-relaxation), two kinds of components—a slow and a fast one—could be identified in the dry state. On the basis of the spatial information provided by neutron scattering, a model for the geometry of the motions involved in the fast component has been proposed. Adding solvent, this process would remain essentially unaltered, but the population involved in the slower one would be reduced. With THF as solvent, this reduction would be complete, but with water it would be only partial. This could be attributed to rather heterogeneous distribution of water molecules in the polymer likely associated with the presence of water clusters. Such a scenario would also explain the much more pronounced broadening of the glass-transition region observed for the polymer in the aqueous mixture with respect to that induced by THF.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000361935600040
DO  - DOI:10.1021/acs.macromol.5b01316
UR  - https://juser.fz-juelich.de/record/281716
ER  -