Dynamic surfactants drive anisotropic colloidal assembly
Yaxin Xu1, Prabhat Jandhyala1, Sho C Takatori1
1Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, California 93117, USA.
The Journal of Chemical Physics
|August 8, 2024
Summary
Colloids with dynamic polymer brushes form unusual anisotropic assemblies, even from simple spherical particles. This dynamic surfactant behavior enables novel self-assembly pathways and complex structures like lamellar and vesicle phases.
Area of Science:
- Soft Matter Physics
- Colloid Science
- Materials Chemistry
Background:
- Colloidal building blocks with dynamic interactions exhibit complex self-assembly.
- Surface-mobile polymer brushes act as 'dynamic surfactants' on colloids.
- Traditional polymer-grafted colloids typically form isotropic assemblies.
Purpose of the Study:
- To investigate the phase behavior of colloids coated with dynamic surfactants.
- To demonstrate the formation of anisotropic macroscopic assemblies from spherical colloids.
- To understand how dynamic surfactant reorganization influences self-assembly pathways.
Main Methods:
- Utilized Brownian Dynamics simulations.
- Employed dynamic density functional theory.
- Analyzed microscopic polymer distributions and their geometric constraints.
Main Results:
- Demonstrated anisotropic macroscopic assemblies from spherical colloids with isotropic interactions.
- Observed time-dependent reorganization of dynamic surfactants leading to novel phase diagrams.
- Identified packing into lamellar, string, and vesicle phases controlled by polymer distributions.
Conclusions:
- Dynamic surfactants on colloidal building blocks enable anisotropic self-assembly.
- This dynamic behavior allows for assembly pathways not achievable with static interactions.
- Offers versatile building blocks with design freedom for non-equilibrium assembly.
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