Visible-Light-Regulated Controlled/Living Radical Polymerization in Miniemulsion

Area of Science:

• Polymer Chemistry
• Green Chemistry
• Photochemistry

Background:

• Photopolymerization in aqueous systems offers sustainable polymer synthesis.
• Previous methods relied on UV irradiation and specialized equipment, limiting accessibility.
• Developing visible light-driven photopolymerization is crucial for greener materials preparation.

Purpose of the Study:

• To develop a greener, more accessible photopolymerization method using visible light.
• To implement photoredox catalysis for controlled/living radical polymerization under visible light.
• To demonstrate the feasibility of photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) in miniemulsion.

Main Methods:

• Utilized photoredox catalysis with a household blue LED (460 nm) for styrene miniemulsion polymerization.
• Employed the photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) process.
• Investigated the effect of light intensity and catalyst concentration on polymerization rate.

Main Results:

• Successfully achieved miniemulsion polymerization of styrene under visible light.
• Demonstrated facile control over polymerization rate via light intensity and catalyst concentration.
• Confirmed temporal control through ON/OFF experiments, showing robustness to light interruptions.

Conclusions:

• Visible light photoredox catalysis offers a greener and more accessible alternative for photopolymerization.
• The PET-RAFT process provides excellent control over polymerization kinetics and temporal aspects.
• This method facilitates sustainable synthesis of polymeric materials in aqueous dispersed systems.