Atom Transfer Radical Polymerization Enabled by Sonochemically Labile Cu-carbonate Species

Area of Science:

• Polymer Chemistry
• Materials Science
• Organic Synthesis

Background:

• Previous ultrasound-mediated Atom Transfer Radical Polymerization (ATRP) methods (sono-ATRP, mechano-ATRP) were slow and resulted in polymer contamination.
• Existing techniques often required specific solvents or additives, limiting their practical application.
• The need for efficient and controlled polymerization methods remains a key challenge in polymer science.

Purpose of the Study:

• To develop a rapid and controlled ultrasound-mediated ATRP process.
• To investigate the role of sodium carbonate in enhancing sono-ATRP.
• To prepare well-defined polyacrylates using a simple and robust method.

Main Methods:

• Atom Transfer Radical Polymerization (ATRP) of methyl acrylate in DMSO.
• Utilized low-intensity ultrasound irradiation in the presence of a copper complex and sodium carbonate.
• Analyzed polymer molecular weights and dispersities (M_w/M_n).

Main Results:

• Achieved rapid polymerization with 80% conversion in under 2 hours.
• Demonstrated excellent control over molecular weights and low dispersities (M_w/M_n < 1.2).
• Identified the formation of a Cu^II/L-CO₃ complex and its role in generating activators and scavenging carbonate radicals.

Conclusions:

• Sodium carbonate significantly accelerates sono-ATRP in DMSO.
• The process is simple, robust, and uses readily available reagents like washing soda or baking soda.
• This method provides a facile route to well-defined polyacrylates using air-stable catalysts and low-intensity ultrasound.