Amphiphilic random copolymers bearing linear poly(oxyethylene) side chains and lateral dendritic wedges: Synthesis and their emulsifying performances

Abstract

In this study, we demonstrated nonaqueous macroemulsions stabilized by amphiphilic random copolymers exhibiting linear poly(oxyethylene) side chains and two-generation dendritic wedges along their backbones, which were synthesized by traditional radical random copolymerization of oligo (ethylene glycol) methyl ether methacrylate (POEGMA) with 2-methyl-2-((2-(4-methyl-1H-1,2,3-triazol-1-yl) ethoxy) carbonyl) propane-1,3-diylbis(2,2,5-trimethyl-1,3-dioxane-5-carboxylate)) methacrylate (MPDMA) in THF using AIBN as initiators. PPOEGMA-ran-PMPDMA copolymers containing different molar fractions of MPDMA monomer unit ranging from 0.28 to 0.65 were achieved through the adjustment of the feed ratio of monomer pairs during the copolymerization. Interfacial tension experiments revealed the critical micelle concentrations of PPOEGMA-ran-PMPDMA copolymers decreased with the increase of the contents of MPDMA monomer unit in copolymer chains. [Bmim][PF6]-in-toluene emulsions were subsequently prepared using amphiphilic PPOEGMA-ran-PMPDMA copolymers as macromolecular emulsifiers. The average size of the emulsion droplets showed an increasing tendency with the increase of the contents of MPDMA monomer unit in random copolymer chains. Under the otherwise identical conditions, the emulsifying performances of PPOEGMA-ran-PMPDMA copolymers were better than those of PPOEGMA-b-PMPDMA diblock copolymer counterparts judging from the size of the emulsion droplets and the stability of the emulsions.