Photopolymerizable Monomer Miniemulsions: Why Does Droplet Size Matter?

In monomer miniemulsions, droplet size is a key parameter impacting the optical properties, and consequently their photopolymerizability under UV light. Three simple spectrophotometric methodologies are developed, based on an integrating sphere, to evaluate precisely the effect of droplet size on radiation absorption and scattering, which both contribute to light attenuation. Using a series of diluted acrylate monomer miniemulsions ranging from 40 to 300 nm, all the methods converge toward a constant absorption coefficient, comparable with that in solution. In contrast, a droplet‐size decrease causes a significant and progressive reduction of the scattering coefficient, with a positive effect on light penetration. magnified image