Recovery of Nanoparticles from (EO)₈(PO)₅₀(EO)₈/p-Xylene/H₂O Microemulsions by Tuning the Temperature

A novel method to prepare nanoparticles using reverse micelles of poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) (PEO−PPO−PEO) block copolymer surfactant was proposed. The method is based on the fact that the critical micellization concentration of some PEO−PPO−PEO block copolymers increases sharply with increasing temperature. Therefore, nanoparticles can be synthesized in the reverse micelles at lower temperatures, and the nanoparticles can be precipitated and recovered with a temperature rise because of the breakage of the reverse micelles. As an example, silver nanoparticles were synthesized in the reverse micelles of (EO) 8 (PO) 50 (EO) 8 / p -xylene/H 2 O and recovered.