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Title: Thermodynamic Model of Solvent Effects in Semiflexible Diblock and Random Copolymer Assembly

Abstract

Here, we present a field-theoretic model to predict the equilibrium thermodynamic behavior of semiflexible diblock copolymers and random copolymers in the presence of solvent. We find that in both systems polymer–solvent contacts dramatically influence the thermodynamic behavior with decreasing the copolymer segment length (i.e., molecular weight). When a copolymer has unequal monomer composition, both polymer length and solvent concentration have a strong influence on the phase transition spinodal and magnitude of the critical wave modes. Diblock copolymers exhibit an expanded region of the lamellar phase in the phase diagram with decreasing chain length and polymer concentration. Such effects suggest a breakdown of the dilute approximation for solutions of short diblock copolymers. Random copolymer solutions also exhibit changes in the phase-transition spinodal and critical wave mode at asymmetric chemical compositions. This effect is highly relevant to most random copolymer materials, since a monomer is typically a low-molecular-weight chemical unit.

Authors:
 [1];  [1];  [1]; ORCiD logo [2]
  1. Stanford Univ., Stanford, CA (United States)
  2. Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1470934
Grant/Contract Number:  
[AC02-76SF00515; 1511373]
Resource Type:
Accepted Manuscript
Journal Name:
Macromolecules
Additional Journal Information:
[ Journal Volume: 51; Journal Issue: 11]; Journal ID: ISSN 0024-9297
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Mao, Shifan, MacPherson, Quinn, Liu, Chunzi, and Spakowitz, Andrew J. Thermodynamic Model of Solvent Effects in Semiflexible Diblock and Random Copolymer Assembly. United States: N. p., 2018. Web. doi:10.1021/acs.macromol.8b00172.
Mao, Shifan, MacPherson, Quinn, Liu, Chunzi, & Spakowitz, Andrew J. Thermodynamic Model of Solvent Effects in Semiflexible Diblock and Random Copolymer Assembly. United States. doi:10.1021/acs.macromol.8b00172.
Mao, Shifan, MacPherson, Quinn, Liu, Chunzi, and Spakowitz, Andrew J. Wed . "Thermodynamic Model of Solvent Effects in Semiflexible Diblock and Random Copolymer Assembly". United States. doi:10.1021/acs.macromol.8b00172. https://www.osti.gov/servlets/purl/1470934.
@article{osti_1470934,
title = {Thermodynamic Model of Solvent Effects in Semiflexible Diblock and Random Copolymer Assembly},
author = {Mao, Shifan and MacPherson, Quinn and Liu, Chunzi and Spakowitz, Andrew J.},
abstractNote = {Here, we present a field-theoretic model to predict the equilibrium thermodynamic behavior of semiflexible diblock copolymers and random copolymers in the presence of solvent. We find that in both systems polymer–solvent contacts dramatically influence the thermodynamic behavior with decreasing the copolymer segment length (i.e., molecular weight). When a copolymer has unequal monomer composition, both polymer length and solvent concentration have a strong influence on the phase transition spinodal and magnitude of the critical wave modes. Diblock copolymers exhibit an expanded region of the lamellar phase in the phase diagram with decreasing chain length and polymer concentration. Such effects suggest a breakdown of the dilute approximation for solutions of short diblock copolymers. Random copolymer solutions also exhibit changes in the phase-transition spinodal and critical wave mode at asymmetric chemical compositions. This effect is highly relevant to most random copolymer materials, since a monomer is typically a low-molecular-weight chemical unit.},
doi = {10.1021/acs.macromol.8b00172},
journal = {Macromolecules},
number = [11],
volume = [51],
place = {United States},
year = {2018},
month = {5}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Figures / Tables:

Figure 1 Figure 1: Directions (arrows) and magnitudes (in color) of spontaneous concentration fluctuations in diblock copolymers at different equilibrium solvent composition $\bar{ϕ_s}$ and monomer compositions $\bar{ϕ_A}$ and $\bar{ϕ_B}$. Top panels are for polymers with N = 1000, Flory–Huggins parameter χAB = 0 (left), and χAB = 0.8χ$*\atop{AB}$. Bottom panels are formore » polymers with N = 1, Flory–Huggins parameter χAB = 0 (left), and χAB = 0.8χ$*\atop{AB}$.« less

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Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.