RAFT Emulsion Polymerization: MacroRAFT Agent Self-Assembly Investigated Using a Solvachromatic Dye

Area of Science:

• Polymer Chemistry
• Materials Science
• Physical Chemistry

Background:

• Polymerization-induced self-assembly (PISA) and macroRAFT-mediated emulsion polymerization are key for creating well-defined polymers.
• The conformational state of macroRAFT agents in aqueous solution is not well understood.

Purpose of the Study:

• To investigate the coil conformation of poly(acrylic acid) (PAA) and poly(methacrylic acid) (PMAA) macroRAFT agents across various pH conditions.
• To compile critical aggregate concentration (CAC) and critical micelle concentration (CMC) values for these systems.

Main Methods:

• Fluorescence spectrometry was employed to study the coil conformation of PAA and PMAA macroRAFT agents.
• Various Z-groups and amphiphilic block copolymers were synthesized and analyzed.

Main Results:

• Detailed investigations of coil conformation were performed for PAA and PMAA macroRAFT agents with different Z-groups and as amphiphilic block copolymers.
• CAC/CMC values were determined, ranging from 7.48 × 10^-7 to 2.57 × 10^-3 mol L^-1.
• An extensive library of CAC/CMC values was compiled for PAA- and PMAA-based macroRAFT agents at different pH levels.

Conclusions:

• The study provides crucial data on macroRAFT agent conformations and aggregation behavior.
• This information is vital for understanding the mechanisms and optimizing macroRAFT-assisted emulsion polymerization processes.