Electrochemically-Initiated RAFT Synthesis of Low Dispersity Multiblock Copolymers by Seeded Emulsion Polymerization

Area of Science:

• Polymer Chemistry
• Materials Science
• Electrochemistry

Background:

• Controlled polymerization techniques are crucial for synthesizing advanced polymer architectures.
• Reversible Addition-Fragmentation chain Transfer (RAFT) polymerization offers control over polymer molecular weight and dispersity.
• Emulsion polymerization provides a scalable route for producing polymer nanoparticles.

Purpose of the Study:

• To introduce and demonstrate an electrochemically initiated emulsion polymerization (eRAFT) method.
• To synthesize well-defined multiblock copolymers with low molar mass dispersity.
• To achieve controlled particle growth and low particle size dispersity in latexes.

Main Methods:

• Utilized electrochemically initiated reversible addition-fragmentation chain transfer (eRAFT) polymerization.
• Employed seeded RAFT emulsion polymerization at ambient temperature (approx. 30 °C).
• Synthesized triblock and tetrablock copolymers using a sequential monomer addition strategy without intermediate purification.

Main Results:

• Successfully synthesized low dispersity multiblock copolymers, including PBMA-b-PSt-b-PMS and PBMA-b-PSt-b-P(BA-stat-St)-b-PSt.
• Achieved high monomer conversions in each polymerization step.
• Obtained predicted molar masses, low molar mass dispersity (Đ ≈ 1.1-1.2), controlled particle sizes (Zav = 100-115 nm), and low particle size dispersity (PDI ≈ 0.02).

Conclusions:

• The emulsion eRAFT process is effective for synthesizing well-defined multiblock copolymers.
• The method leverages compartmentalization and nanoreactor concepts for precise control.
• This approach offers a straightforward and scalable route to advanced polymer latexes.