Distribution of Alternating Sequences in Methyl Methacrylate/ n-Butyl Acrylate Copolymers Prepared by Atom Transfer Radical Polymerization

Copolymers of n-butyl acrylate/methyl methacrylate (BA/MMA) with certain compositions were recently proposed as self-healing materials due to "key-and-lock" interchain interactions of alternating sequences. This inspired us to analyze by numerical simulations the formation of heterosequences in BA/MMA copolymers prepared by atom transfer radical polymerization (ATRP). Stochastic Monte Carlo and deterministic simulations using numerical integration of differential equations showed that the highest contribution of alternating sequences is present in a statistical copolymer with 1:1 BA/MMA composition. However, batch ATRP of a 1:1 BA/MMA mixture generates a gradient copolymer with a diminished fraction of alternating sequences. Therefore, a method for preparing a statistical BA/MMA copolymer with the highest fraction of alternating sequences is proposed through normal ATRP copolymerization with feeding of MMA. The contribution of heterosequences was analyzed for both batch ATRP systems and in the presence of feeding, to identify the conditions that maximize the amount of alternating sequences in the copolymers.