Electrochemically mediated atom transfer radical polymerization on nonconducting substrates: controlled brush growth through catalyst diffusion.

Surface initiated atom transfer radical polymerization (SI-ATRP) was triggered after diffusion of a Cu(I)/L activator generated at a working electrode. A stable [Cu(II)L]/[Cu(I)L] ratio gradient was formed at the gap between the working electrode and the initiator terminated substrate due to ion diffusion. The size of the gap can be used to dictate polymer growth kinetics at different gap distances. Gradient polymer brushes were grafted when substrate was placed at a tilting angle along [Cu(II)L]/[Cu(I)L] gradient.