Surface modification of Janus particles and their compatibilization in polymer blends

Janus particles with biphasic polymer brushes are promising as compatibilizers in biphasic systems due to the combination of both the particle core and the amphiphilic properties of the two compartment faces. As the traditional colloid particles, the compatibilization efficiency of Janus particles also scales with the increased amphiphilicity of particles by both phases and the enlarging of the interfacial tension aside from the increase in the radius of the particles. Meanwhile, the interfacial tension between the demixing polymer liquids is quite low, therefore a precise control over the surface chemistry of particles is absolutely necessary for the improved accomodation of particles by polymer blends and the compatibilization efficiency. In this paper, the Janus particles with rubber brushes (polybutadiene, PBd-SiO2@PDVB; polyisoprene, PI-SiO2@PDVB) are synthesized by surface modification on a snowman like Janus particle (SiO2@PDVB) template, from which PBd and PI brushes are previously synthesized by anionic polymerization, followed by their covalently attached onto SiO2 surface of JP cores. Adding such modified Janus particles into polystyrene (PS)/PI or PS/PBd blends enables offsetting to some extent the stronger interaction between PS phases and PDVB hemispheres. Resultantly, PBd-SiO2@PDVB and PI-SiO2@PDVB particles character as the better efficiency in compatibilization than SiO2@PDVB particles, which reflected as the smaller PS phase distributed in the rubber matrix. It is expected this article could contribute to the advances in the application of Janus particles in polymer blends.