Stabilizing Effect of PS-b-PMMA Diblock Copolymers in PS/PMMA-Based THF-in-THF Emulsions

Area of Science:

• Polymer Science
• Materials Chemistry
• Colloid Science

Background:

• Emulsion stability is crucial in various chemical applications.
• Polystyrene (PS) and poly(methyl methacrylate) (PMMA) are common polymers used in solvent-based systems.
• Diblock copolymers can influence the behavior of polymer blends and emulsions.

Purpose of the Study:

• To investigate the stabilization effect of PS-b-PMMA diblock copolymers in PS/PMMA solvent-based emulsions.
• To understand the role of copolymer concentration, composition, and phase volume fraction on emulsion stability.
• To elucidate the mechanism of stabilization at the molecular level.

Main Methods:

• Visual inspection and confocal laser scanning microscopy (CLSM) for macroscopic and microscopic stability assessment.
• Static and dynamic light scattering (SLS/DLS) to study the behavior of PS-b-PMMA in homopolymer solutions.
• Investigation across various phase volume fractions, concentrations, and copolymer compositions.

Main Results:

• PS-b-PMMA diblock copolymers were observed to form micelles above a critical homopolymer concentration.
• Addition of small amounts of homopolymer to micelle solutions led to spontaneous incorporation into the micelles.
• CLSM and visual analysis confirmed the emulsion stabilization effect attributed to the diblock copolymer.

Conclusions:

• The observed emulsion stability is attributed to the formation of a laminar layer of the diblock copolymer at the interface of dispersed droplets.
• This interfacial layer, formed by the diblock copolymer, effectively prevents droplet coalescence.
• The study highlights the effectiveness of PS-b-PMMA diblock copolymers as stabilizers in PS/PMMA solvent-based emulsions.