Copper-mediated living radical polymerization (SET-LRP) of lipophilic monomers from multi-functional initiators : reducing star–star coupling at high molecular weights and high monomer conversions

The SET-LRP of lipophilic monomers (n-butyl and lauryl acrylate) from a lactose based octa-functional initiator is described. A range of highly defined lipophilic poly(acrylate) stars are prepared to relatively high molecular weights (Mn,target > 100 000 g mol−1 in some cases) and high monomer conversions (≥99%) with excellent control retained over molecular weight distributions (PDI values as low as 1.03). Phase separation of star polymers from the reaction media during polymerization is seen to occur which is advantageous in reducing star–star coupling in certain cases, without limiting the attainment of near quantitative conversions. A comparison is made between heterogeneous and homogeneous polymerization protocols to illustrate this finding.