Particle morphology of carboxylated poly(n-butyl acrylate)/poly(methyl methacrylate) composite latex particles

Particles with a copolymer soft core of poly(n-butyl acrylate)/poly(methyl methacrylate) (PBuA/PMMA) and a homopolymer hard shell of PMMA were synthezied by in-situ seeded, two stage polymerization process. The single particle morphology was characterized using transmission electron microscopy (TEM), atomic force microscopy (AFM) and solid-state NMR. The phase ratio as one important parameter was investigated having a strong influence on the particle morphology. A series of core-to-shell ratios from 100/0 (wt%) to 25/75 were synthesized and characterized. The combination of TEM, AFM and solid-state NMR allows quantitative determination of the extent of coverage of the core by the shell polymer and the interphase thickness, both were found to depend on the shell content.