Preparation and surface modification of highly dispersed nano-ZnO with stearic acid activated by N,N′-carbonyldiimidazole

Hydrophobic ZnO nanoparticles were produced and a novel surface treatment process was developed to obtain highly dispersed and long-term stabile ZnO nanoparticles in organic matrix. The aminopropyl triethoxysilane (APS) was grafted on the surface of ZnO nanoparticles, and long carbon chain of stearic acid (SA) was introduced through condensation reaction between APS and the activated SA with N,N′-carbonyldiimidazole (CDI). ZnO nanoparticles were characterized by FITR, TGA, SEM and sedimentation test. The results showed that the CDI activator of SA can effectively promote the condensation reaction between APS and SA and enhance the dispersion and long-term stability of modified ZnO nanoparticles in organic solvent.

Research Highlights
► A novel surface treatment process for ZnO nanoparticles was developed.
► CDI promote effectively the reaction between SA and APS.
► The aggregates of ZnO nanoparticles were considerably reduced.
► The long-term stability of ZnO nanoparticles was obviously improved.