In this paper, the possibilities offered by anionic polymerization were exploited to engineer well-defined PS-b-PEO2 gemini-type dispersants that were fitted with terminal styrenic groups. Two routes were explored to obtain this novel generation of surfactants whose thorough characterization indicated that they exhibit the expected molecular structure. These reactive block copolymers have been subsequently used as surfactants in the emulsion polymerization of styrene to stabilize the colloidal particles formed. The kinetics of polymerization in the presence of such reactive surfactants were shown to differ from the case involving PS-b-PEO linear macromonomers as surfactants.

Monodisperse core−shell latex particles functionalized with surface groups that were introduced by the macromonomer technique were obtained by means of a two-step emulsion polymerization process in a batch reactor at 70 °C. In the first step the cores were synthesized by means of a batch emulsion polymerization of styrene (St), and in the second step, the shells were formed by batch emulsion copolymerizations of St and different macromonomers using the seeds obtained previously. Macromonomers were synthesized by anionic “living” polymerization. They are constituted of a poly(ethylene oxide) hydrophilic block and a hydrophobic block or sequence end-fitted with an unsaturation. The latexes were characterized by gravimetry, transmission electron microscopy (TEM), and conductometric titrations to obtain the conversion, the particle size distribution (PSD), and the surface charge density (σ), respectively. The colloidal stability of the cores and final latexes were determined by measuring the critical coagulation concentration (CCC) at two pHs (7 and 2) using KBr as electrolyte. The surface charges of the latexes were moderately low, with corresponding moderately low CCCs. The presence of spacers, confirmed with a disk centrifuge photosedimentometer (DCP) and photon correlation spectrophotometer (PCS), did not increase the CCC. During the CCC measurements, at high electrolyte concentrations, the reduced solubility of the spacer PEO moiety in the solution resulted in its collapse on the particle surface.