Enhancing Mechanically Induced ATRP by Promoting Interfacial Electron Transfer from Piezoelectric Nanoparticles to Cu Catalysts

A robust mechanically controlled atom transfer radical polymerization (mechano-ATRP) was developed by enhancing the interaction between piezoelectric nanoparticles and ATRP Cu catalysts. The interactions favor a mechano-induced electron transfer from the surface of the nanoparticles to the deactivator CuII/L complex under ultrasonic agitation, promoting the formation of the activator CuI/L complex, thereby increasing the rate of the polymerization. This mechano-ATRP was carried out with a low loading of zinc oxide nanoparticles, providing a polymer with high end-group fidelity, predetermined molecular weight, and low dispersity. Propagation of the polymer chains was switched on/off in response to the ultrasound. The effects of the nature of the nanoparticle, nanoparticle loading, and targeted degrees of polymerization were investigated to evaluate the mechanism of mechano-ATRP.