Short-Time Dynamics of PDMS- g-PDMS Bottlebrush Polymer Melts Investigated by Quasi-Elastic Neutron Scattering

Karin J. Bichler; Bruno Jakobi; Victoria García Sakai; Alice Klapproth; Richard A. Mole; Gerald J. Schneider

doi:10.1021/acs.macromol.0c01846

Short-Time Dynamics of PDMS- g-PDMS Bottlebrush Polymer Melts Investigated by Quasi-Elastic Neutron Scattering

Karin J. Bichler, Bruno Jakobi, Victoria García Sakai, Alice Klapproth, Richard A. Mole, Gerald J. Schneider

Research output: Contribution to journal › Article › peer-review

17 Scopus citations

Abstract

We have studied the short-time dynamical behavior of polydimethylsiloxane (PDMS) bottlebrush polymers, PDMS-g-PDMS. The samples have similar backbone lengths but different side-chain lengths, resulting in a shape transition. Quasi-elastic neutron scattering was used to observe the dynamical changes inherent to these structural changes. The combination of data from three spectrometers enabled to follow the dynamics over broad frequency and temperature ranges, which included segmental relaxations and more localized motions. The latter, identified as the methyl group rotation, is described by a threefold jump model and shows higher activation energies compared to linear PDMS. The segmental relaxation times, τs, decrease with increasing molecular weight of the side chains but increase with momentum transfer, Q, following a power law, which suggests a non-Gaussian behavior for bottlebrush polymers.

Original language	English
Pages (from-to)	9553-9562
Number of pages	10
Journal	Macromolecules
Volume	53
Issue number	21
DOIs	https://doi.org/10.1021/acs.macromol.0c01846
State	Published - Nov 10 2020
Externally published	Yes

Funding

We acknowledge funding by the U.S. Department of Energy (DoE) under grant DE-SC0019050. We are also grateful for the access to the neutron scattering instruments, provided by ACNS, Sydney, Australia (P7387 and P7389) and the ISIS Neutron and Muon Facility (DOI: 10.5286/ISIS.E.RB1910220).

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title = "Short-Time Dynamics of PDMS- g-PDMS Bottlebrush Polymer Melts Investigated by Quasi-Elastic Neutron Scattering",

abstract = "We have studied the short-time dynamical behavior of polydimethylsiloxane (PDMS) bottlebrush polymers, PDMS-g-PDMS. The samples have similar backbone lengths but different side-chain lengths, resulting in a shape transition. Quasi-elastic neutron scattering was used to observe the dynamical changes inherent to these structural changes. The combination of data from three spectrometers enabled to follow the dynamics over broad frequency and temperature ranges, which included segmental relaxations and more localized motions. The latter, identified as the methyl group rotation, is described by a threefold jump model and shows higher activation energies compared to linear PDMS. The segmental relaxation times, τs, decrease with increasing molecular weight of the side chains but increase with momentum transfer, Q, following a power law, which suggests a non-Gaussian behavior for bottlebrush polymers.",

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AU - Bichler, Karin J.

AU - Jakobi, Bruno

AU - Sakai, Victoria García

AU - Klapproth, Alice

AU - Mole, Richard A.

AU - Schneider, Gerald J.

PY - 2020/11/10

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Short-Time Dynamics of PDMS- g-PDMS Bottlebrush Polymer Melts Investigated by Quasi-Elastic Neutron Scattering

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