Synergistic Polymer-Surfactant-Complex Mediated Colloidal Interactions and Deposition
Helya Najafi1, Huda A Jerri2, Valentina Valmacco3
1Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States.
ACS Applied Materials & Interfaces
|March 4, 2020
Summary
Total internal reflection microscopy (TIRM) reveals how polymer-surfactant mixtures control colloidal deposition. Specific compositions promote or prevent particle adhesion through synergistic interactions, guiding formulation design.
Area of Science:
- Colloid and Surface Science
- Materials Science
- Physical Chemistry
Background:
- Understanding colloid-surface interactions is crucial for controlling deposition in formulations.
- Polymer-surfactant mixtures create complex interfacial environments.
- Selective colloidal deposition is vital in applications like coatings and personal care products.
Purpose of the Study:
- To directly measure colloidal interactions, dynamics, and deposition in polymer-surfactant systems.
- To construct a deposition state diagram for various polymer-surfactant compositions.
- To elucidate the mechanisms governing colloid-surface interactions in these complex mixtures.
Main Methods:
- Total Internal Reflection Microscopy (TIRM) for direct, sensitive measurement.
- Characterization of bulk polymer-surfactant phase behavior.
- Analysis of surface properties and colloid-substrate interaction potentials.
Main Results:
- A comprehensive deposition state diagram was generated across four decades of polymer and surfactant concentrations.
- Colloid-substrate interactions and deposition behavior exhibited nonmonotonic and synergistic trends.
- Specific polymer-surfactant compositions induced bridging/depletion attractions or electrosteric repulsion.
Conclusions:
- Polymer-surfactant complexes dictate colloidal deposition mechanisms.
- Synergistic effects, not simple superposition, govern interactions.
- Findings provide insights for controlling selective colloidal deposition in multicomponent formulations.
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