Molecular brushes based on copolymers of alkoxy oligo(ethylene glycol) methacrylates and dodecyl(meth)acrylate: features of synthesis by conventional free radical polymerization

Amphiphilic copolymer molecular brushes of three different types with side chains consisting of alkyl and oligo(ethylene glycol) blocks based on higher alkoxy oligo(ethylene glycol) methacrylates (HAOEGM), methoxy oligo(ethylene glycol) methacrylates (MOEGM) and dodecyl(meth)acrylate have been successfully synthesized via conventional radical polymerization in toluene. In case of the copolymerization of HAOEGM with MOEGM, the monomer reactivity ratios were independent of the structure of higher alkyl groups (C-12-C-18) and the degree of ethoxylation (n = 6-11) and were equal to 0.76-0.81 and 1.19-1.27, respectively. In case of the copolymerization of HAOEGM or MOEGM with dodecyl methacrylate, the reactivity ratios were even closer to each other (1.00-1.17). Applicability of the reactivity ratios calculated at low conversions for estimating copolymer compositions at high conversions was shown. In all systems, compositionally homogeneous copolymers with a narrow molecular weight distribution were formed. For the HAOEGM (C-12,n = 9)-dodecyl acrylate monomer system, the reactivity ratios were 0.88 and 0.25 and the resulting copolymers had high compositional heterogeneity.

Automated summary

Three different types of amphiphilic copolymer molecular brushes with side chains consisting of alkyl and oligo(ethylene glycol) blocks were successfully synthesized via conventional radical polymerization in toluene. The reactivity ratios calculated for the copolymerization of different monomers showed independence of the alkyl group structure and ethoxylation degree, leading to compositionally homogeneous copolymers. Overall, the study demonstrated the applicability of reactivity ratios for estimating copolymer compositions at high conversions.