Photocatalyzed dimethylacrylamide polymerization in an aqueous solution using 4-nitrophenylacetylene-modified Cu2O crystals

Abstract

Cu₂O cubes, octahedra, and rhombic dodecahedra with and without surface 4-nitrophenylacetylene (4-NA) functionalization were used to catalyze dimethylacrylamide (DMA) photopolymerization in water. Among these samples, the 4-NA-modified Cu₂O cubes presented a highest monomer conversion percentage of 69% after 1 h of 420 nm light irradiation, possibly due to the most efficient electron transfer from the particles to the Ph₂ICl co-initiator. The synthesized polymers generally have high molecular weights and good dispersity values. The reaction can be easily scaled up 10 fold under room light. After simple particle removal, a transparent gel-like polymer product is obtained. The Cu₂O crystals can be recycled for use in more polymerization reactions. Electron and hole scavenging experiments were conducted to support the proposed reaction mechanism. This work shows surface-controlled semiconductor nanocrystals can be simple yet highly effective photocatalysts for some polymerization reactions.