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Updated: Jul 5, 2025
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Assembly and Characterization of Polyelectrolyte Complex Micelles
Published on: March 2, 2020
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Assessing the Structure and Equilibrium Conditions of Complex Coacervate Core Micelles by Varying Their Shell
Júlia Bonesso Sabadini1, Cristiano Luis Pinto Oliveira2, Watson Loh1
1Institute of Chemistry, University of Campinas (UNICAMP), P.O. Box 6154, 13083-970 Campinas, São Paulo, Brazil.
Langmuir : the ACS Journal of Surfaces and Colloids
|January 19, 2024
Summary
Complex coacervate core micelles (C3Ms) are stable under specific conditions, with size and structure influenced by neutral block density and ionic strength. Understanding these factors is key for C3M applications.
Area of Science:
- Polymer Science
- Materials Science
- Physical Chemistry
Background:
- Complex coacervates form via phase separation of oppositely charged polyelectrolytes.
- Complex coacervate core micelles (C3Ms) are nanometric aggregates formed from charged-neutral diblock copolymers and oppositely charged homopolymers.
- The thermodynamic and kinetic stability of C3Ms remains a subject of debate.
Purpose of the Study:
- To investigate the stability and structural characteristics of C3Ms formed from poly(diallyldimethylammonium) and poly(acrylamide)-b-poly(acrylate).
- To determine the influence of preparation protocols, aging, neutral block density, and ionic strength on C3M stability and structure.
Main Methods:
- Dynamic light scattering (DLS) to assess aggregate size and stability.
- Small-angle X-ray scattering (SAXS) to analyze C3M structure and phase separation.
- Systematic variation of preparation protocols, copolymer concentration, and ionic strength.
Main Results:
- C3Ms exhibit equilibrium conditions, showing no variation with preparation protocols or aging.
- Aggregate size increases with decreased neutral block density in the shell, while maintaining a globular shape.
- Higher ionic strengths and partial replacement of copolymer with homopolymer can lead to metastable states and eventual phase separation via micelle coagulation.
Conclusions:
- Equilibrium C3Ms are generally achieved near a 1:1 charge stoichiometry.
- C3M stability and structure are sensitive to shell density and ionic strength, with deviations from equilibrium observed under specific conditions.
- These findings provide crucial insights for the targeted application of C3Ms.
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