Elucidating the Nucleation Event in the C–C Cross-Coupling Step-Growth Dispersion Polymerization

Step-growth dispersion polymerization is a powerful method to produce uniform and monodisperse particles of π-conjugated polymers with tunable sizes. While the growth period in such step-growth dispersion polymerizations is well understood, it remains unknown whether or not the nucleation process comprises an aggregation or coalescence step. Only a complete understanding of the entire mechanism of particle formation during step-growth dispersion polymerization will provide information about the morphology inside of the polymer particles and enable design of synthesis strategies to give access to more sophisticated particle architectures, such as core–shell or patchy particles. We employ spectroscopic and light scattering analysis to shed light on the nucleation event in a Heck-type C–C cross-coupling dispersion polymerization. In contrast to the typical mechanism, our dispersion polymerization of conjugated polymer particles does not feature the aggregation step.