Journal Article

FZJ-2019-06146

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Polymer dynamics under confinement

Richter, D. (Corresponding author)FZJ* ; Kruteva, M.FZJ*

2019
Royal Soc. of Chemistry London

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Please use a persistent id in citations: doi:10.1039/C9SM01141B

Abstract: We review recent neutron scattering work and related results from simulation and complementary techniques focusing on the microscopic dynamics of polymers under confinement. Confinement is either realized in model porous materials or in polymer nanocomposites (PNC). The dynamics of such confined polymers is affected on the local segmental level, the level of entanglements as well as on global levels: (i) at the segmental level the interaction with the surface is of key importance. At locally repulsive surfaces compared to the bulk the segmental dynamics is not altered. Attractive surfaces slow down the segmental dynamics in their neighborhood but do not give rise to dead, glassy layers. (ii) Confinement generally has little effect on the inter-chain entanglements: both for weakly as well as for marginally confined polymers the reptation tube size is not changed. Only for strongly confined polymers disentanglement takes place. Similarly, in PNC at higher NP loading disentanglement phenomena are observed; in addition, at very high loading a transition from polymer caused topological constraints to purely geometrical constraints is observed. (iii) On the more global scale NSE experiments revealed important information on the nature of the interphase between adsorbed layer and bulk polymer. (iv) Polymer grafts at NP mutually confine each other, an effect that is most pronounced for one component NP. (v) Global diffusion of entangled polymers both in weakly and strongly attractive PNC is governed by the ratio of bottle-neck to chain size that characterizes the ‘entropic barrier’ for global diffusion.

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

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Contributing Institute(s):

1. JCNS-FRM-II (JCNS-FRM-II)
2. Heinz Maier-Leibnitz Zentrum (MLZ)
3. Neutronenstreuung (JCNS-1)
4. Streumethoden (JCNS-2)

Research Program(s):

1. 6215 - Soft Matter, Health and Life Sciences (POF3-621) (POF3-621)
2. 6G15 - FRM II / MLZ (POF3-6G15) (POF3-6G15)
3. 6G4 - Jülich Centre for Neutron Research (JCNS) (POF3-623) (POF3-623)

Experiment(s):

1. J-NSE: Neutron spin-echo spectrometer (NL2ao)
2. KWS-1: Small angle scattering diffractometer (NL3b)
3. SNS-NSE: Neutron Spin Echo Spectrometer

Appears in the scientific report 2019

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Database coverage:
; Allianz-Lizenz / DFG ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; IF < 5 ; JCR ; National-Konsortium ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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