Fabrication of inverse core–shell and Janus-structured microspheres of blends of poly(4-butyltriphenylamine) and poly(methyl methacrylate)

We here report the facile fabrication of inverse core–shell and Janus structured particles consisting of poly(4-butyltriphenylamine) (PBTPA) and poly(methyl methacrylate) (PMMA) via a solvent evaporation from solution droplets of a polymer blend dispersed in an aqueous phase. Janus structured composite particles in which the PBTPA domain was partially coated by the PMMA domain were obtained using poly(vinyl alcohol) (PVA) as a suspension stabilizer. On the other hand, when sodium dodecyl sulfate (SDS) was added as a surfactant together with PVA, “inverse core–shell” particles in which the PMMA core was covered by the PBTPA shell were formed as well as Janus particles. TEM observation showed that the PMMA core was located at the center of the sphere and PBTPA layer has uniform thickness in inverse core–shell particles. The increase of the composition of PBTPA or the concentration of SDS increased the ratio of the inverse core–shell particles to the Janus ones. Graphical abstract