We evaluated the relationship between reaction conditions and the diameter of particles produced by SEM (Fig. , Table ). Spherical particles with diameters less than 1 µm were observed under all conditions, supporting the progression of precipitation polymerization . In the experiment with the highest concentration (Run 1), the particle diameter was approximately 0.4 µm. In contrast, in Runs 2 and 3, where the concentration during polymerization was reduced, the particle size decreased to 0.5 and 0.4 µm, respectively. As the concentration of the monomer decreases, the rate of nucleation and growth of particles slows down while the solubility improves. Because the product's particle size is determined after such complex interactions, there is no simple rule to connect the experimental conditions, the reaction solution's appearance, and the product's structure . In the future, we plan to comprehensively analyze the effects of monomer concentration, solvent conditions, temperature, and other factors on microparticles' precipitation behavior and particle size. The experiments will be automatically done by robots, and foundational models should support analysis.