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

Mao, Shifan; MacPherson, Quinn; Liu, Chunzi; Spakowitz, Andrew J.

doi:10.1021/acs.macromol.8b00172

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:

Mao, Shifan ^[1]; MacPherson, Quinn ^[1]; Liu, Chunzi ^[1];

^[2]

Stanford Univ., Stanford, CA (United States)
Stanford Univ., Stanford, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)

Publication Date:: 2018-05-23

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.  https://doi.org/10.1021/acs.macromol.8b00172.

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                    Mao, Shifan, MacPherson, Quinn, Liu, Chunzi, & Spakowitz, Andrew J. Thermodynamic Model of Solvent Effects in Semiflexible Diblock and Random Copolymer Assembly.  United States.  https://doi.org/10.1021/acs.macromol.8b00172

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                    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.  https://doi.org/10.1021/acs.macromol.8b00172.  https://www.osti.gov/servlets/purl/1470934.

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@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}

}

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https://doi.org/10.1021/acs.macromol.8b00172

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Figures / Tables:

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 χ_AB = 0 (left), and χ_AB = 0.8χ$*\atop{AB}$. Bottom panels are formore »

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