Journal Article

FZJ-2016-01404

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Influence of Solvent on Poly(2-(Dimethylamino)Ethyl Methacrylate) Dynamics in Polymer-Concentrated Mixtures: A Combined Neutron Scattering, Dielectric Spectroscopy, and Calorimetric Study

Goracci, G. (Corresponding author) ; Arbe, A. ; Alegría, A. ; García Sakai, V. ; Rudić, S. ; Schneider, G. J.FZJ* ; Lohstroh, W. ; Juranyi, F. ; Colmenero, J.

2015
Soc. Washington, DC

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Please use a persistent id in citations: doi:10.1021/acs.macromol.5b01316

Abstract: 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.

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

Note: "final draft post referee" kann nicht beigebracht werden

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)
2. Neutronenstreuung (Neutronenstreuung ; JCNS-1)

Research Program(s):

1. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
2. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)

Experiment(s):

1. SPHERES: Backscattering spectrometer (NL6S)
2. TOFTOF: Cold neutron time-of-flight spectrometer (NL2au)

Appears in the scientific report 2015

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Database coverage:
; Current Contents - Physical, Chemical and Earth Sciences ; IF >= 5 ; JCR ; NCBI Molecular Biology Database ; No Authors Fulltext ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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