A Process for Well-Defined Polymer Synthesis through Textile Dyeing Inspired Catalyst Immobilization

Industrialized textile dyeing technology has inspired a scalable and low-cost process for immobilization of a photoredox catalyst onto commercial cotton threads to prepare unique heterogeneous catalyst composites; these composites are capable of regulating photoinduced controlled/living radical polymerization in batch and flow reactors. Free base porphyrin (e.g., tetraphenylporphyrin (TPP)), an efficient photocatalyst for photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer polymerization of acrylamides, was attached to the cotton thread through a method analogous to reactive dye chemistry, to produce composites with excellent photocatalytic activity. Separation and recovery of the catalyst-functionalized composite was realized through simple washing with solvents, which resulted in negligible catalyst leaching and maintenance of catalytic performance over multiple polymerization cycles. Polymerization was also successfully performed in solvents where TPP has poor solubility, demonstrating the versatility of this approach. By taking advantage of the robustness and flexibility of cotton thread, the immobilized catalyst was fitted in a continuous flow reactor to prepare well-defined polymers through a flow process.