Block copolymer micelles as seed in emulsion polymerization

The size of aggregates formed by poly(acrylic acid)-black-poly(methyl metha crylate) block copolymers was determined and the applicability of these blo ck copolymers as stabilizers in emulsion polymerization was investigated. T he analytical methods included transmission electron microscopy, light scat tering, and analytical ultracentrifugation. Polymers with a hydrophilic pol y(acrylic acid) block of equal or larger size than the hydrophobic poly(met hyl methacrylate) block are efficient as stabilizers down to block copolyme r-to-monomer ratios of less than 1 wt.-%. From the influence of the block c opolymer-to-monomer ratio on the latex particle size, from the relation bet ween the number of block copolymer molecules per latex particle and the agg regation number of the block copolymer micelles, and from fluorescence stud ies we conclude that micelles consisting of block copolymers with 35 or mor e hydrophobic MMA units act as a seed in the emulsion polymerization of acr ylic and methacrylic monomers.