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Title: Effect of Gradient Sequencing on Copolymer Order-Disorder Transitions: Phase Behavior of Styrene/n-Butyl Acrylate Block and Gradient Copolymers

Abstract

We investigate the effect of gradient sequence distribution in copolymers on order-disorder transitions, using rheometry and small-angle X-ray scattering to compare the phase behavior of styrene/n-butyl acrylate (S/nBA) block and gradient copolymers. Relative to block sequencing, gradient sequencing increases the molecular weight necessary to induce phase segregation by over 3-fold, directly consistent with previous predictions from theory. Results also suggest the existence of both upper and lower order-disorder transitions in a higher molecular weight S/nBA gradient copolymer, made accessible by the shift in order-disorder temperatures from gradient sequencing. The combination of transitions is speculated to be inaccessible in S/nBA block copolymer systems due to their overlap at even modest molecular weights and also their location on the phase diagram relative to the polystyrene glass transition temperature. Finally, we discuss the potential impacts of polydispersity and chain-to-chain monomer sequence variation on gradient copolymer phase segregation.

Authors:
; ;  [1];  [2]
  1. NWU
  2. (
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Science Foundation (NSF)
OSTI Identifier:
1049552
Resource Type:
Journal Article
Journal Name:
Macromolecules
Additional Journal Information:
Journal Volume: 44; Journal Issue: (15) ; 08, 2011
Country of Publication:
United States
Language:
ENGLISH
Subject:
36 MATERIALS SCIENCE; ACRYLATES; COPOLYMERS; DISTRIBUTION; GLASS; MOLECULAR WEIGHT; MONOMERS; PHASE DIAGRAMS; POLYSTYRENE; SCATTERING; SEGREGATION; TRANSITION TEMPERATURE

Citation Formats

Mok, Michelle M, Ellison, Christopher J, Torkelson, John M, and UMM). Effect of Gradient Sequencing on Copolymer Order-Disorder Transitions: Phase Behavior of Styrene/n-Butyl Acrylate Block and Gradient Copolymers. United States: N. p., 2012. Web. doi:10.1021/ma201080n.
Mok, Michelle M, Ellison, Christopher J, Torkelson, John M, & UMM). Effect of Gradient Sequencing on Copolymer Order-Disorder Transitions: Phase Behavior of Styrene/n-Butyl Acrylate Block and Gradient Copolymers. United States. doi:10.1021/ma201080n.
Mok, Michelle M, Ellison, Christopher J, Torkelson, John M, and UMM). Wed . "Effect of Gradient Sequencing on Copolymer Order-Disorder Transitions: Phase Behavior of Styrene/n-Butyl Acrylate Block and Gradient Copolymers". United States. doi:10.1021/ma201080n.
@article{osti_1049552,
title = {Effect of Gradient Sequencing on Copolymer Order-Disorder Transitions: Phase Behavior of Styrene/n-Butyl Acrylate Block and Gradient Copolymers},
author = {Mok, Michelle M and Ellison, Christopher J and Torkelson, John M and UMM)},
abstractNote = {We investigate the effect of gradient sequence distribution in copolymers on order-disorder transitions, using rheometry and small-angle X-ray scattering to compare the phase behavior of styrene/n-butyl acrylate (S/nBA) block and gradient copolymers. Relative to block sequencing, gradient sequencing increases the molecular weight necessary to induce phase segregation by over 3-fold, directly consistent with previous predictions from theory. Results also suggest the existence of both upper and lower order-disorder transitions in a higher molecular weight S/nBA gradient copolymer, made accessible by the shift in order-disorder temperatures from gradient sequencing. The combination of transitions is speculated to be inaccessible in S/nBA block copolymer systems due to their overlap at even modest molecular weights and also their location on the phase diagram relative to the polystyrene glass transition temperature. Finally, we discuss the potential impacts of polydispersity and chain-to-chain monomer sequence variation on gradient copolymer phase segregation.},
doi = {10.1021/ma201080n},
journal = {Macromolecules},
number = (15) ; 08, 2011,
volume = 44,
place = {United States},
year = {2012},
month = {11}
}