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Designing Multicomponent Polymer Colloids for Self-Stratifying Films.
Piyush K Singh, Michaeleen L Pacholski1, Junsi Gu1
1The Dow Chemical Company, Collegeville, Pennsylvania 19426-2914, United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|September 2, 2022
Summary
Understanding polymer molecular weight and heat aging is key for self-stratifying coatings. Unentangled polymers enable rapid phase separation, while entangled ones show slow separation due to kinetic limits.
Area of Science:
- Materials Science
- Polymer Science
- Coatings Technology
Background:
- Aqueous polymer colloids (latexes) are vital in coatings.
- Multicomponent latexes with core-shell morphology enable self-stratifying coatings for single-step complex structures.
- Developing these materials requires understanding phase separation and transport properties.
Purpose of the Study:
- Investigate phase separation and self-stratification in acrylic-silicone latex films.
- Determine the influence of shell polymer molecular weight and heat aging on film morphology.
- Explore the relationship between film rheology and morphological changes.
Main Methods:
- Fabrication of core-shell acrylic (shell) and acrylic-silicone (core) latex films.
- Thermal aging of films under various conditions.
- Morphological analysis using Transmission Electron Microscopy (TEM).
- Rheological characterization using linear shear rheology.
Main Results:
- Shell polymer molecular weight and heat aging critically control phase separation.
- Unentangled shell polymers facilitate rapid phase separation (hours) at moderate temperatures.
- Entangled shell polymers significantly hinder phase separation (months) due to kinetic limitations.
- Latex film rheological properties are highly sensitive to morphological evolution.
Conclusions:
- Shell polymer architecture and thermal history dictate self-stratification efficiency.
- Bulk rheology offers a straightforward method for monitoring morphological changes in multicomponent latex films.
- This research provides insights for designing advanced self-stratifying coating materials.
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