Hemispherical polymer nano-particles of polyisoprene–poly(methyl methacrylate) blend with core–shell structure

We show a simple preparation procedure of particles with unique shape and inner structures of polymer blend. Submicron sized particles consisting of polyisoprene (PI) and poly(methyl methacrylate) (PMMA) were prepared by adding a poor solvent (water) into a tetrahydrofuran (THF) solution of these polymers and following evaporation of THF. The diameter and shape of particles were controlled by changing the concentration of the solution. After selective staining of PI by osmium tetraoxide, particles were observed by scanning transmission electron microscopy (STEM). The observation showed the hemispherical particles with PI core and PMMA shell were formed. After dispersion of the stained particles into THF, the hemispherical particles of the cross-linked PI core were obtained by the selective dissolution of PMMA shell.