Catenated PS-PMMA block copolymers via supramolecularly templated ATRP initiator approach

A novel route to synthesize catenated macrocyclic PS-PMMA block copolymers is demonstrated via combination of supramolecular chemistry and controlled radical polymerization (CRP). Polymerization of styrene with bromopropionate ester initiator coupled with phenanthroline Cu(I) complex affords a four arm PS macroinitiator, which upon further chain extension by polymerization of MMA generates a four arm PS-PMMA block copolymer. Intramolecular coupling of PS-PMMA-Br arms via low temperature styrene-assisted atom transfer radical coupling (ATRC) leads to the formation of PS-PMMA catenand, which generates the metal-free catenated macrocyclic PS-PMMA block copolymer after removal of Cu metal. The interlocked structures of catenated block copolymers are confirmed by GPC, NMR, and AFM image analysis.