Shedding light on surfactant-free emulsion polymerization

Abstract

Herein, we introduce a sustainable method for latex production via surfactant-free emulsion polymerization (SFEP) carrying out a photoinitiated polymerization (photo-SFEP) under both artificial light and sunlight. We discuss the use of sodium phenyl-2,4,6-trimethylbenzoylphosphinate (TPO-Na) as a water-soluble photoinitiator to in situ prepare polymeric nanoparticles under mild conditions, eliminating the need of conventional surfactants. The methodology exploits the rapid photolysis of TPO-Na, which generates anionic radical species that initiate the polymerization of glycidyl methacrylate (GlyMA), selected as a model monomer. Photo-SFEP was optimized to ensure colloidal stability over several months, even under varying environmental ionic strengths. The structural and colloidal properties of the nanoparticles were thoroughly characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), and zeta potential measurements, confirming the reproducibility and robustness of the latex dispersions. Our methodology shows promise as a scalable, efficient alternative to conventional emulsion polymerization techniques. Additionally, its versatility was affirmed by extending its application to various vinylic monomers, showcasing its broad potential.