Salt effect on microscopic structure and stability of colloidal complex obtained from neutral/polyelectrolyte block copolymer and oppositely charged surfactant

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The salt effect on complex formation of poly(acrylamide)-block-poly(acrylic acid) (PAM-b-PAA) and dodecyltrimethylammonium bromide (DTAB) at different NaBr concentrations, C NaBr, was investigated by laser light scattering (LLS) and small angle neutron scattering (SANS). LLS and SANS clearly indicates that the aqueous solution of PAM-b-PAA and DTAB associate into colloidal complexes. For low surfactant-to-polymer charge ratio Z lower than the critical value Z C, the colloidal complexes are single DTAB micelles dressed by a few PAM-b-PAA. Above Z C, the colloidal complexes form a core-shell microstructure. The complex formation in the PAM-b-PAA/DTAB is enhanced by addition of salt: Z C decreases with increasing C NaBr. This is considered to similar to the cmc behavior for the pure surfactant system. The core of the complex consists of densely packed surfactant micelles (DTA +), and PAA block chains bind to these micelles, displace their counteranions (Br-) and bridge them. The corona of the complex is constituted from the PAM. Since the interaction between polyelectrolyte and oppositely charged surfactant is primarily electrostatic in nature, the core radius and the intermicellar distance of the DTA + micelles inside the core depend on C NaBr. The addition of salt screens the electrostatic attraction between oppositely charged PAA block and DTAB, which weakens the interaction. With increasing C NaBr, therefore, the core of the colloidal complex is considered to swell, which leads to the increases in the core radius R C and the intermicellar distance of the DTA + micelles inside the core. The aggregation number expressed in terms of DTA + micelles per complex is also evaluated using the analogy with the homopolyelectrolyte/surfactant system.

Original languageEnglish
Pages (from-to)127-135
Number of pages9
JournalColloids and Surfaces B: Biointerfaces
Volume99
DOIs
Publication statusPublished - Nov 1 2012

Fingerprint

carbopol 940
Micelles
Polyelectrolytes
block copolymers
Surface-Active Agents
Block copolymers
Surface active agents
Acrylamide
Salts
surfactants
micelles
salts
Polyacrylates
Differential thermal analysis
bromides
acrylic acid
Acrylics
thermal analysis
Small Angle Scattering
Acids

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Surfaces and Interfaces
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

@article{cdf8f57bef0843749f3910cbece505ae,
title = "Salt effect on microscopic structure and stability of colloidal complex obtained from neutral/polyelectrolyte block copolymer and oppositely charged surfactant",
abstract = "The salt effect on complex formation of poly(acrylamide)-block-poly(acrylic acid) (PAM-b-PAA) and dodecyltrimethylammonium bromide (DTAB) at different NaBr concentrations, C NaBr, was investigated by laser light scattering (LLS) and small angle neutron scattering (SANS). LLS and SANS clearly indicates that the aqueous solution of PAM-b-PAA and DTAB associate into colloidal complexes. For low surfactant-to-polymer charge ratio Z lower than the critical value Z C, the colloidal complexes are single DTAB micelles dressed by a few PAM-b-PAA. Above Z C, the colloidal complexes form a core-shell microstructure. The complex formation in the PAM-b-PAA/DTAB is enhanced by addition of salt: Z C decreases with increasing C NaBr. This is considered to similar to the cmc behavior for the pure surfactant system. The core of the complex consists of densely packed surfactant micelles (DTA +), and PAA block chains bind to these micelles, displace their counteranions (Br-) and bridge them. The corona of the complex is constituted from the PAM. Since the interaction between polyelectrolyte and oppositely charged surfactant is primarily electrostatic in nature, the core radius and the intermicellar distance of the DTA + micelles inside the core depend on C NaBr. The addition of salt screens the electrostatic attraction between oppositely charged PAA block and DTAB, which weakens the interaction. With increasing C NaBr, therefore, the core of the colloidal complex is considered to swell, which leads to the increases in the core radius R C and the intermicellar distance of the DTA + micelles inside the core. The aggregation number expressed in terms of DTA + micelles per complex is also evaluated using the analogy with the homopolyelectrolyte/surfactant system.",
author = "Annaka Masahiko",
year = "2012",
month = "11",
day = "1",
doi = "10.1016/j.colsurfb.2011.11.021",
language = "English",
volume = "99",
pages = "127--135",
journal = "Colloids and Surfaces B: Biointerfaces",
issn = "0927-7765",
publisher = "Elsevier",

}

TY - JOUR

T1 - Salt effect on microscopic structure and stability of colloidal complex obtained from neutral/polyelectrolyte block copolymer and oppositely charged surfactant

AU - Masahiko, Annaka

PY - 2012/11/1

Y1 - 2012/11/1

N2 - The salt effect on complex formation of poly(acrylamide)-block-poly(acrylic acid) (PAM-b-PAA) and dodecyltrimethylammonium bromide (DTAB) at different NaBr concentrations, C NaBr, was investigated by laser light scattering (LLS) and small angle neutron scattering (SANS). LLS and SANS clearly indicates that the aqueous solution of PAM-b-PAA and DTAB associate into colloidal complexes. For low surfactant-to-polymer charge ratio Z lower than the critical value Z C, the colloidal complexes are single DTAB micelles dressed by a few PAM-b-PAA. Above Z C, the colloidal complexes form a core-shell microstructure. The complex formation in the PAM-b-PAA/DTAB is enhanced by addition of salt: Z C decreases with increasing C NaBr. This is considered to similar to the cmc behavior for the pure surfactant system. The core of the complex consists of densely packed surfactant micelles (DTA +), and PAA block chains bind to these micelles, displace their counteranions (Br-) and bridge them. The corona of the complex is constituted from the PAM. Since the interaction between polyelectrolyte and oppositely charged surfactant is primarily electrostatic in nature, the core radius and the intermicellar distance of the DTA + micelles inside the core depend on C NaBr. The addition of salt screens the electrostatic attraction between oppositely charged PAA block and DTAB, which weakens the interaction. With increasing C NaBr, therefore, the core of the colloidal complex is considered to swell, which leads to the increases in the core radius R C and the intermicellar distance of the DTA + micelles inside the core. The aggregation number expressed in terms of DTA + micelles per complex is also evaluated using the analogy with the homopolyelectrolyte/surfactant system.

AB - The salt effect on complex formation of poly(acrylamide)-block-poly(acrylic acid) (PAM-b-PAA) and dodecyltrimethylammonium bromide (DTAB) at different NaBr concentrations, C NaBr, was investigated by laser light scattering (LLS) and small angle neutron scattering (SANS). LLS and SANS clearly indicates that the aqueous solution of PAM-b-PAA and DTAB associate into colloidal complexes. For low surfactant-to-polymer charge ratio Z lower than the critical value Z C, the colloidal complexes are single DTAB micelles dressed by a few PAM-b-PAA. Above Z C, the colloidal complexes form a core-shell microstructure. The complex formation in the PAM-b-PAA/DTAB is enhanced by addition of salt: Z C decreases with increasing C NaBr. This is considered to similar to the cmc behavior for the pure surfactant system. The core of the complex consists of densely packed surfactant micelles (DTA +), and PAA block chains bind to these micelles, displace their counteranions (Br-) and bridge them. The corona of the complex is constituted from the PAM. Since the interaction between polyelectrolyte and oppositely charged surfactant is primarily electrostatic in nature, the core radius and the intermicellar distance of the DTA + micelles inside the core depend on C NaBr. The addition of salt screens the electrostatic attraction between oppositely charged PAA block and DTAB, which weakens the interaction. With increasing C NaBr, therefore, the core of the colloidal complex is considered to swell, which leads to the increases in the core radius R C and the intermicellar distance of the DTA + micelles inside the core. The aggregation number expressed in terms of DTA + micelles per complex is also evaluated using the analogy with the homopolyelectrolyte/surfactant system.

UR - http://www.scopus.com/inward/record.url?scp=84863871311&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84863871311&partnerID=8YFLogxK

U2 - 10.1016/j.colsurfb.2011.11.021

DO - 10.1016/j.colsurfb.2011.11.021

M3 - Article

C2 - 22197735

AN - SCOPUS:84863871311

VL - 99

SP - 127

EP - 135

JO - Colloids and Surfaces B: Biointerfaces

JF - Colloids and Surfaces B: Biointerfaces

SN - 0927-7765

ER -