Mass-produce sub-15 nm polymeric soft-nanoparticles and cold-flow conditions

Polymeric soft-nanoparticles (SNPs) synthesized via microemulsion polymerization, are widely used in both academia and industry. However, achieving a significantly smaller diameter still presents a challenge. Despite the use of excess surfactants, surface tension constraints prevent microemulsion droplets from decreasing in diameter below 20 nm. Still using conventional surfactants, we introduce a simple and efficient method for mass production of SNPs down to 10–15 nm in diameter. The microemulsion is prepared by incorporating solvents that are good for both monomers and polymers. This method effectively yields significantly smaller SNPs. In the melts of such small SNPs, the Rouse-like viscous-dominant behavior is observed and fully mapped with respect to the diameter and degree of cross-linking. This was previously not observed in microemulsion polymerized SNPs. We assess the cold flow conditions by determining the ability to form transparent sheets from the powder at room temperature when subjected to pressure. It is governed by the diameter and degree of crosslinking. The ultrasmall SNPs thus have the potential to be used as fillers in various industries.