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Multistage hydrophilic core/hydrophobic shell latexes containing carboxyl groups were prepared via multistep seeded emulsion copolymerization, and particles with different morphologies were obtained after alkali post-treatment. Influences of the type and content of unsaturated acid monomer on the polymerization and the particle morphology were investigated based on conductometric titration and TEM observation. Results showed that the hydrophilic core/hydrophobic shell particles could be easily formed using methacrylic acid (MAA) instead of acrylic acid. When MAA was 12.2 wt % in the core latex preparation, only fine pores existed inside the alkali-treated particles. With MAA increased from 20.0 to 30.0 wt %, the alkali-treated particle morphology evolved from porous, hollow to collapse structure. When MAA further increased to 40.0 wt %, it was difficult to prepare uniform multistage particles and distinct morphologies including solid, deficient swelling, hollow and collapse structure were coexistent in the alkali-treated particles. Moreover, the forming mechanism of different morphologies was proposed.

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Covalently-colored polymer latex was synthesized via batch emulsion copolymerization of styrene, butyl acrylate and methacrylic acid in the presence of red polymerizable dye monomer consisting of anthraquinone chromophore, alkyl spacer and acryloyl group, and the influences of the initiator, surfactant and polymerizable dye on the polymerization and the latex properties were investigated. Results showed that the initiator amount was a determinative factor for the monomer conversion, and a high conversion of the polymerizable dye could be achieved when the ammonium persulfate amount was equal to or more than 1 wt% to the total monomers. Most of the chromophores were covalently bonded to the polymer chains if the polymerizable dye was used in the range of 0-1.5 wt%. The light fastness of the resulting latex film was much better than that of the noncovalently-colored polymer film.

Soap-free hydrophilic-hydrophobic core-shell latex particles with high carboxyl content in the core of the particles were synthesized via the seeded emulsion polymerization using methyl methacrylate (MMA), butyl acrylate (BA), methacrylic acid (MAA), styrene (St) and ethylene glycol dimethacrylate (EGDMA) as monomers, and the influences of MMA content used in the core preparation on polymerization, particle size and morphology were investigated by transmission electron microscopy, dynamic light scattering and conductometric titration. The results showed that the seeded emulsion polymerization could be carried out smoothly using "starved monomer feeding process" when MAA content in the core preparation was equal to or less than 24 wt%, and the encapsulating efficiency of the hydrophilic P(MMA-BA-MAA-EGDMA) core with the hydrophobic PSt shell decreased with the increase in MAA content. When an interlayer of P(MMA-MAA-St) with moderate polarity was inserted between the P(MMA-BA-MAA-EGDMA) core and the PSt shell, well designed soap-free hydrophilic-hydrophobic core-shell latex particles with 24 wt% MAA content in the core preparation were obtained.