Thermomechanical Behavior and Local Dynamics of Dendronized Block Copolymers and Constituent Homopolymers
Abstract
We employ Brillouin light scattering (BLS) and dielectic spectroscopy (DS) to study the phononic behavior, thermomechanical properties, and segmental dynamics of symmetric block copolymers (BCP) constructed from discrete wedge-type repeat units and the corresponding dendronized constituent homopolymers over a broad temperature range. In spite of the sufficiently large elastic contrast between the bulk homopolymers, for the BCPs an absence of a bandgap in the phonon dispersion relation along the periodicity direction implies different modified sound velocities in the photonic BCP lamellar films. The anticipated rich segmental dynamics reveal interfacial mixing as well as confinement effects of the two blocks. This class of amorphous dendronized homopolymers and BCPs reveal strong effects of the wedge-like side groups manifested in the vastly different glass transition temperatures (T_g), free-volume domination of the temperature dependence of the elastic modulus, and heterogeneous segmental dynamics represented by four relaxation processes.
Additional Information
© 2015 American Chemical Society. Received: April 15, 2015; Revised: May 19, 2015; Published: June 2, 2015. This work was cofinanced by the E.U.-European Social Fund and the Greek Ministry of Development-GSRT in the framework of the program THALIS. The current work was supported by the Research unit on Dynamics and Thermodynamics of the UoI cofinanced by the European Union and the Greek state under NSRF 2007-2013 (Region of Epirus, call 18). The work carried out at Caltech was supported by the Camille and Henry Dreyfus Postdoctoral Program in Environmental Chemistry. A.A. thanks Elena Alonso for the technical assistance in the BLS experiment.Attached Files
Supplemental Material - ma5b00779_si_001.pdf
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Additional details
- Eprint ID
- 59005
- DOI
- 10.1021/acs.macromol.5b00779
- Resolver ID
- CaltechAUTHORS:20150724-100034747
- European Social Fund
- Greek Ministry of Development
- European Union
- NSRF 2007-2013
- Camille and Henry Dreyfus Foundation
- Created
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2015-07-24Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field