Popcorn-like morphology of asymmetric nanoparticles co-adjusted by hydrophilicity and crosslinking degree of the seeds

Abstract

This paper presents a facile synthesis method for poly(methyl methacrylate-co-acetoacetoxyethyl methacrylate)–polystyrene popcorn-like particles by soap-free seeded emulsion polymerization. In this study, popcorn-like, raspberry-like and reverse core–shell structures of the P(MMA-co-AAEM)–PS particles could be obtained in a reliable manner. And it was found that the hydrophilicity and crosslinking degree of the seed particles, which were respectively controlled by the addition amount of comonomer AAEM and crosslinker ethyleneglycol dimethacrylate in the P(MMA-co-AAEM) seed particles, co-adjusted the popcorn-like morphology of P(MMA-co-AAEM)–PS particles. In order to make sense of the formation mechanism of the morphology, a thermodynamic model utilizing an equilibrium among the elastic-retractile force of the cross-linked polymer network, the mixing force of monomer and polymer and the interfacial tension force between the particle and water, was used to explain the formation of anisotropic particles.