The challenge is that most techniques measure the size of nondeformable polymer or inorganic particles, while monomer droplets are soft, volatile, deformable, and can lose monomer by diffusionto the surrounding medium. Sample preparation, such as required for dynamic light scattering (DLS), can easily change the DSD before it can be observed. In this work, the particle sizing techniques of capillary hydrodynamic fractionation (CHDF) and acoustic attenuation spectroscopy (AAS) were adapted for droplet sizing.