Synthesis of crosslinked poly(methacrylic acid) shell/lipid core colloidal nanoparticles via L-in-L_m interfacial polymerization and their pH responsiveness

Viriyakitpattana N.,Sunintaboon P.

Department of Chemistry, Faculty of Science, Mahidol University, Rama VI Road, Phyathai, 10400, Thailand

In this present work, the synthesis of colloidal nanoparticles with crosslinked poly(methacrylic acid) (PMAA)-shell and lipid core via L-in-L_m interfacial polymerization was illustrated. The oil-in-water pre-emulsion of lipid (L) dispersed in an aqueous continuous phase containing monomer (L_m) was initially formed, and the polymerization took place at the oil/water interface. The oil phase contained sunflower oil (SF) as a model lipid and benzoyl peroxide (BPO) initiator, while an aqueous continuous phase consisted of methacrylic acid (MAA) as a model monomer, N,N’-methylenebis(acrylamide) (MBA) as cross-linker, and sodium dodecyl sulfate (SDS) as surfactant. After polymerization at elevated temperature, crosslinked PMAA was located on the surface of sunflower oil droplets as a shell layer, indicating that MAA monomer and MBA cross-linker were involved in the polymerization at the oil/water interface. The detailed investigation on the effects of polymerization parameters (e.g. polymerization temperature, initiator, monomer, surfactant, and cross-linker concentrations) was conducted. The physico-chemical properties, such as particle size, morphology, chemical composition, and pH-responsiveness were then determined. This synthetic route can provide PMAA-shell nanoparticles with accessibility and availability of carboxyl functional groups, and pH responsiveness that could be useful for various applications.