Catenated PS-PMMA Block Copolymers via Supramolecularly Templated ATRP Initiator Approach

A novel route to synthesize catenated macrocyclic PSPMMA 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 PSPMMA block copolymer. Intramolecular coupling of PSPMMABr arms via low temperature styrene-assisted atom transfer radical coupling (ATRC) leads to the formation of PSPMMA catenand, which generates the metal-free catenated macrocyclic PSPMMA block copolymer after removal of Cu metal. The interlocked structures of catenated block copolymers are confirmed by GPC, NMR, and AFM image analysis.