skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Amphiphilic Bottlebrush Block Copolymers: Analysis of Aqueous Self-Assembly by Small-Angle Neutron Scattering and Surface Tension Measurements

Abstract

A systematic series of 16 amphiphilic bottlebrush block copolymers (BCPs) containing polystyrene and poly(N-acryloylmorpholine) (PACMO) side chains were prepared by a combination of atom-transfer radical polymerization (ATRP), photoiniferter polymerization, and ring-opening metathesis polymerization (ROMP). The grafting-through method used to prepare the polymers enabled a high degree of control over backbone and side-chain molar masses for each block. Surface tension measurements on the self-assembled amphiphilic bottlebrush BCPs in water revealed an ultralow critical micelle concentration (cmc), 1–2 orders of magnitude lower than linear BCP analogues on a molar basis, even for micelles with >90% PACMO content. Combined with coarse-grained molecular dynamics simulations, fitting of small-angle neutron scattering traces (SANS) allowed us to evaluate solution conformations for individual bottlebrush BCPs and micellar nanostructures for self-assembled macromolecules. Bottlebrush BCPs showed an increase in anisotropy with increasing PACMO content in toluene-d 8, which is a good solvent for both blocks, reflecting an extended conformation for the PACMO block. SANS traces of bottlebrush BCPs assembled into micelles in D 2O, a selective solvent for PACMO, were fitted to a core–shell–shell model, suggesting the presence of a partially hydrated inner shell. Here, results showed an average micelle diameter of 40 nm with combined shell diameters rangingmore » from 16 to 18 nm. A general trend of increased stability of micelles (i.e., resistance to precipitation) was observed with increases in PACMO content. These results demonstrate the stability of bottlebrush polymer micelles, which self-assemble to form spherical micelles with ultralow (<70 nmol/L) cmc’s across a broad range of compositions.« less

Authors:
 [1];  [2];  [1]; ORCiD logo [3]; ORCiD logo [4];  [2]; ORCiD logo [3]; ORCiD logo [5]; ORCiD logo [5]; ORCiD logo [2]; ORCiD logo [1]
  1. Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States). Dept. of Chemistry and Macromolecules Innovation Inst.
  2. Rice Univ., Houston, TX (United States). Dept. of Chemical and Biomolecular Engineering
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Neutron Scattering Division; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS)
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS), and Computational Sciences and Engineering Division
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1489558
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Macromolecules
Additional Journal Information:
Journal Name: Macromolecules; Journal ID: ISSN 0024-9297
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Alaboalirat, Mohammed, Qi, Luqing, Arrington, Kyle J., Qian, Shuo, Keum, Jong K., Mei, Hao, Littrell, Kenneth C., Sumpter, Bobby G., Carrillo, Jan-Michael Y., Verduzco, Rafael, and Matson, John B.. Amphiphilic Bottlebrush Block Copolymers: Analysis of Aqueous Self-Assembly by Small-Angle Neutron Scattering and Surface Tension Measurements. United States: N. p., 2018. Web. doi:10.1021/acs.macromol.8b02366.
Alaboalirat, Mohammed, Qi, Luqing, Arrington, Kyle J., Qian, Shuo, Keum, Jong K., Mei, Hao, Littrell, Kenneth C., Sumpter, Bobby G., Carrillo, Jan-Michael Y., Verduzco, Rafael, & Matson, John B.. Amphiphilic Bottlebrush Block Copolymers: Analysis of Aqueous Self-Assembly by Small-Angle Neutron Scattering and Surface Tension Measurements. United States. doi:10.1021/acs.macromol.8b02366.
Alaboalirat, Mohammed, Qi, Luqing, Arrington, Kyle J., Qian, Shuo, Keum, Jong K., Mei, Hao, Littrell, Kenneth C., Sumpter, Bobby G., Carrillo, Jan-Michael Y., Verduzco, Rafael, and Matson, John B.. Mon . "Amphiphilic Bottlebrush Block Copolymers: Analysis of Aqueous Self-Assembly by Small-Angle Neutron Scattering and Surface Tension Measurements". United States. doi:10.1021/acs.macromol.8b02366.
@article{osti_1489558,
title = {Amphiphilic Bottlebrush Block Copolymers: Analysis of Aqueous Self-Assembly by Small-Angle Neutron Scattering and Surface Tension Measurements},
author = {Alaboalirat, Mohammed and Qi, Luqing and Arrington, Kyle J. and Qian, Shuo and Keum, Jong K. and Mei, Hao and Littrell, Kenneth C. and Sumpter, Bobby G. and Carrillo, Jan-Michael Y. and Verduzco, Rafael and Matson, John B.},
abstractNote = {A systematic series of 16 amphiphilic bottlebrush block copolymers (BCPs) containing polystyrene and poly(N-acryloylmorpholine) (PACMO) side chains were prepared by a combination of atom-transfer radical polymerization (ATRP), photoiniferter polymerization, and ring-opening metathesis polymerization (ROMP). The grafting-through method used to prepare the polymers enabled a high degree of control over backbone and side-chain molar masses for each block. Surface tension measurements on the self-assembled amphiphilic bottlebrush BCPs in water revealed an ultralow critical micelle concentration (cmc), 1–2 orders of magnitude lower than linear BCP analogues on a molar basis, even for micelles with >90% PACMO content. Combined with coarse-grained molecular dynamics simulations, fitting of small-angle neutron scattering traces (SANS) allowed us to evaluate solution conformations for individual bottlebrush BCPs and micellar nanostructures for self-assembled macromolecules. Bottlebrush BCPs showed an increase in anisotropy with increasing PACMO content in toluene-d8, which is a good solvent for both blocks, reflecting an extended conformation for the PACMO block. SANS traces of bottlebrush BCPs assembled into micelles in D2O, a selective solvent for PACMO, were fitted to a core–shell–shell model, suggesting the presence of a partially hydrated inner shell. Here, results showed an average micelle diameter of 40 nm with combined shell diameters ranging from 16 to 18 nm. A general trend of increased stability of micelles (i.e., resistance to precipitation) was observed with increases in PACMO content. These results demonstrate the stability of bottlebrush polymer micelles, which self-assemble to form spherical micelles with ultralow (<70 nmol/L) cmc’s across a broad range of compositions.},
doi = {10.1021/acs.macromol.8b02366},
journal = {Macromolecules},
issn = {0024-9297},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on December 31, 2019
Publisher's Version of Record

Save / Share: