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Complexes of Charged-Neutral Block Copolymers and Surfactants : Process-Dependent Features and Long-Term Stability of Their Aqueous Dispersions

Ferreira, Guilherme A. ; Ram-On, Maor ; Talmon, Yeshayahu ; Schillén, Karin LU orcid ; Piculell, Lennart LU and Loh, Watson LU (2023) In Langmuir : the ACS journal of surfaces and colloids 39(11). p.4113-4124
Abstract
Aqueous dispersions of charged-neutral block copolymers (poly(acrylamide)-b-poly(acrylate)) complexed with an oppositely charged surfactant (dodecyltrimethylammonium) have been prepared by different approaches: the simple mixing of two solutions (MS approach) containing the block copolymer and surfactant, with their respective simple counterions, and dispersion of a freeze-dried complex salt prepared in the absence of simple counterions (CS approach). The CS particles were investigated under different conditions: dispersion of a CS in salt-free water and dispersion of a CS in a dilute salt solution, the latter condition yielding dispersions with the same composition as the MS process. Additionally, aged dispersions (up to 6 months)... (More)
Aqueous dispersions of charged-neutral block copolymers (poly(acrylamide)-b-poly(acrylate)) complexed with an oppositely charged surfactant (dodecyltrimethylammonium) have been prepared by different approaches: the simple mixing of two solutions (MS approach) containing the block copolymer and surfactant, with their respective simple counterions, and dispersion of a freeze-dried complex salt prepared in the absence of simple counterions (CS approach). The CS particles were investigated under different conditions: dispersion of a CS in salt-free water and dispersion of a CS in a dilute salt solution, the latter condition yielding dispersions with the same composition as the MS process. Additionally, aged dispersions (up to 6 months) and dispersed complexes of the polyacrylate homopolymer and dodecyltrimethylammonium surfactant were evaluated. By employing different characterization techniques, it was seen that dispersions prepared by the MS approach display nanometric spherical particles with disordered cores, and poor colloidal stability, partially caused by the absence of surface charge (ζ-potential close to zero). Oppositely, anisometric particles were formed in CS dispersions and were large enough to sustain micellar cubic cores. The CS particles presented long-time colloidal stability, partially due to a net negative surface charge, but the stability varied with the length of the neutral block composing the corona. Our results demonstrate that all dispersed particles are metastable structures, with physicochemical properties strongly dependent on the preparation procedure, thus making these particles suitable for fundamental studies and potential applications where accurate control of their properties, including size, shape, internal structure, and stability, is desired. (Less)
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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Colloidal particles, Colloids, Copolymers, Surfactants, X-ray scattering
in
Langmuir : the ACS journal of surfaces and colloids
volume
39
issue
11
pages
4113 - 4124
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85149743107
  • pmid:36881854
ISSN
0743-7463
DOI
10.1021/acs.langmuir.2c03500
language
English
LU publication?
yes
id
aff8f85d-ab11-47da-99f8-b4ac48c9c994
date added to LUP
2023-03-15 08:21:23
date last changed
2024-06-13 15:32:08
@article{aff8f85d-ab11-47da-99f8-b4ac48c9c994,
  abstract     = {{Aqueous dispersions of charged-neutral block copolymers (poly(acrylamide)-<i>b</i>-poly(acrylate)) complexed with an oppositely charged surfactant (dodecyltrimethylammonium) have been prepared by different approaches: the simple mixing of two solutions (MS approach) containing the block copolymer and surfactant, with their respective simple counterions, and dispersion of a freeze-dried complex salt prepared in the absence of simple counterions (CS approach). The CS particles were investigated under different conditions: dispersion of a CS in salt-free water and dispersion of a CS in a dilute salt solution, the latter condition yielding dispersions with the same composition as the MS process. Additionally, aged dispersions (up to 6 months) and dispersed complexes of the polyacrylate homopolymer and dodecyltrimethylammonium surfactant were evaluated. By employing different characterization techniques, it was seen that dispersions prepared by the MS approach display nanometric spherical particles with disordered cores, and poor colloidal stability, partially caused by the absence of surface charge (ζ-potential close to zero). Oppositely, anisometric particles were formed in CS dispersions and were large enough to sustain micellar cubic cores. The CS particles presented long-time colloidal stability, partially due to a net negative surface charge, but the stability varied with the length of the neutral block composing the corona. Our results demonstrate that all dispersed particles are metastable structures, with physicochemical properties strongly dependent on the preparation procedure, thus making these particles suitable for fundamental studies and potential applications where accurate control of their properties, including size, shape, internal structure, and stability, is desired.}},
  author       = {{Ferreira, Guilherme A. and Ram-On, Maor and Talmon, Yeshayahu and Schillén, Karin and Piculell, Lennart and Loh, Watson}},
  issn         = {{0743-7463}},
  keywords     = {{Colloidal particles; Colloids; Copolymers; Surfactants; X-ray scattering}},
  language     = {{eng}},
  month        = {{03}},
  number       = {{11}},
  pages        = {{4113--4124}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{Langmuir : the ACS journal of surfaces and colloids}},
  title        = {{Complexes of Charged-Neutral Block Copolymers and Surfactants : Process-Dependent Features and Long-Term Stability of Their Aqueous Dispersions}},
  url          = {{http://dx.doi.org/10.1021/acs.langmuir.2c03500}},
  doi          = {{10.1021/acs.langmuir.2c03500}},
  volume       = {{39}},
  year         = {{2023}},
}