Description: Polymer Chain Conformation and Dynamical Confinement in a Model One-Component Nanocomposite

This title appears in the Scientific Report : 2017

Polymer Chain Conformation and Dynamical Confinement in a Model One-Component Nanocomposite

We report a neutron-scattering investigation on the structure and dynamics of a single-component nanocomposite based on SiO2 particles that were grafted with polyisoprene chains at the entanglement limit. By skillful labeling, we access both the monomer density in the corona as well as the conformat...

Personal Name(s):	Mark, C.
	Holderer, O. / Allgaier, J. / Hübner, E. / Pyckhout-Hintzen, W. / Zamponi, M. / Radulescu, A. / Feoktystov, A. / Monkenbusch, M. (Corresponding author) / Jalarvo, N. / Richter, D.
Contributing Institute:	Neutronenstreuung; JCNS-1 JCNS-SNS; JCNS-SNS JCNS-FRM-II; JCNS-FRM-II Neutronenstreuung; ICS-1
Published in:	Physical review letters, 119 (2017) 4, S. 047801
Imprint:	College Park, Md. APS 2017
DOI:	10.1103/PhysRevLett.119.047801
Document Type:	Journal Article
Research Program:	Soft Matter, Health and Life Sciences Jülich Centre for Neutron Research (JCNS) Functional Macromolecules and Complexes
Subject (ZB):	Soft Condensed Matter > 0 Polymers, Soft Nano Particles and Proteins > 0
Link:	OpenAccess OpenAccess
	Publikationsportal JuSER

Please use the identifier: http://dx.doi.org/10.1103/PhysRevLett.119.047801 in citations.
Please use the identifier: http://hdl.handle.net/2128/14986 in citations.

We report a neutron-scattering investigation on the structure and dynamics of a single-component nanocomposite based on SiO2 particles that were grafted with polyisoprene chains at the entanglement limit. By skillful labeling, we access both the monomer density in the corona as well as the conformation of the grafted chains. While the corona profile follows a r−1 power law, the conformation of a grafted chain is identical to that of a chain in a reference melt, implying a high mutual penetration of the coronas from different particles. The brush crowding leads to topological confinement of the chain dynamics: (i) At local scales, the segmental dynamics is unchanged compared to the reference melt, while (ii) at the scale of the chain, the dynamics appears to be slowed down; (iii) by performing a mode analysis in terms of end-fixed Rouse chains, the slower dynamics is tracked to topological confinement within the cone spanned by the adjacent grafts; (iv) by adding 50% matrix chains, the topological confinement sensed by the grafted chain is lifted partially and the apparent chain motion is accelerated. We observe a crossover from pure Rouse motion at short times to topological confined motion beyond the time when the segmental mean squared displacement has reached the distance to the next graft.