Hydrophilicity of composite latex particles prepared with a particular seeded emulsion polymerization techniques

Various kinds of styrene–(meth)acrylate and (meth)acrylate lattices were prepared by conventional emulsion and seeded emulsion polymerizations as the references for the particular poly(methyl methacrylate-co-methyl acrylate)/poly(dimethylaminoethyl methacrylate-co-styrene) (PMMA-MA/PDM-ST) composite latex prepared by the regulated coagulation process during the seeded polymerization. The contact angle measurement—pendant droplets of distilled-deionized water being dropped on the dried films of these lattices—was performed in order to evaluate the improved hydrophilicity of the PMMA-MA/PDM-ST latex in comparison with those prepared by the conventional processes. The contact angle of the PMMA-MA/PDM-ST film was lower than those of the (meth)acrylate lattices due to the presence of DM-rich domains on the surface. The degree of wetting was controllable by changing the emulsifier content, co-monomer composition and the secondary monomer to seed polymer ratio (M/P). This unique seeded emulsion polymerization process can be applied for productions of outdoor paints.