Mechanism of Synthesizing Sulfur-Rich Polymer Nanoparticles and Their Surface Modification

Abstract

Recent surge of global energy consumption causes a sharp increase in sulfur production as it is produced as a byproduct of natural gas and oil refining operations. With sulfur and sulfur-containing materials exhibiting an array of desirable properties ranging from high electrochemical capacities to high refractive indices, methods of directly utilizing cheap and abundant sulfur for advanced materials is of great interest. One major hurdle against achieving such useful materials from elemental sulfur is the low solubility in common solvents. In order to fully exploit the desirable properties of elemental sulfur, methods to prepare high sulfur-content materials in processible form are crucial. We herein report the synthesis mechanism and surface modification of sulfur-rich polymer nanoparticles (NPs) from interfacial polymerization of sodium polysulfide and 1, 2, 3-trichloropropane in water. Among three types of surfactants (anionic, neutral, and cationic), well-defined spherical shape NPs are obtained only in case of cationic surfactant. This is because only cationic surfactant can transfer the anionic polysulfide into micelle (role of Phase Transfer Catalyst). Synthesizing NPs by using neutral surfactants and PTC, proposed mechanism can be proved in indirect way. The surface of polysulfide nanoparticles could be functionalized first by using end-modified surfactants followed by the UV induced radical addition reaction. The method allows for the preparation of stable polysulfide nanoparticles with positively charged surfaces.