Light and Acid-Base Dual-Regulated Atom Transfer Radical Polymerization With ppb Concentrations of Zwitterionic...

Area of Science:

• Polymer Chemistry
• Photocatalysis
• Organic Synthesis

Background:

• Photoinduced atom transfer radical polymerization (photoATRP) offers precise control over polymer synthesis.
• Development of efficient and responsive photocatalysts is crucial for advancing photoATRP.
• Existing photocatalysts often require high concentrations or lack sensitivity to external stimuli.

Purpose of the Study:

• To introduce novel zwitterionic photocatalysts (PCs) for highly efficient and stimuli-responsive photoATRP.
• To investigate the mechanism of photocatalysis and the effect of acid/base conditions.
• To demonstrate dual regulation of polymerization using light and pH stimuli.

Main Methods:

• Synthesis of zwitterionic photocatalysts with electron-withdrawing substituents.
• Characterization of photocatalyst properties including light absorption and excited state reduction potential.
• Evaluation of photocatalytic activity in photoATRP of acrylates under visible light.
• Investigation of acid/base responsiveness and temporal control via light and pH switching.

Main Results:

• Developed highly efficient zwitterionic PCs with visible light absorption and strong reducing excited states.
• Achieved photoATRP with high initiation efficiency and excellent control (Đ < 1.1) at ultra-low PC concentrations (100 ppb).
• Demonstrated loss of photocatalytic activity in acidic conditions and successful dual regulation of polymerization.

Conclusions:

• The novel zwitterionic PCs exhibit superior performance compared to traditional photocatalysts in photoATRP.
• Acid/base responsiveness allows for strict temporal control over polymer chain growth.
• This work presents the first dual-regulated polymerization using ppb-level photocatalyst concentrations.