ZnO@PNIPAM nanospheres synthesis from inverse Pickering miniemulsion polymerization

Abstract Zinc oxide (ZnO) @ poly (N-isopropyl acrylamide (NIPAM)) (PNIPAM) nanospheres, which the modified ZnO nanoparticles had attached on the interface-layer of PNIPAM, were a special structure material prepared by inverse Pickering miniemulsion polymerization. The original ZnO nanoparticles were synthesized by the sol-gel method and then their surfaces were modified to be partly hydrophobic. The NIPAM inverse Pickering miniemulsion was polymerized to form ZnO@PNIPAM nanospheres, using the modified ZnO nanoparticles as a solid surfactant. The influences of the dosage ratios of modifier to original ZnO nanoparticles on size, distribution and surface hydrophobicity of the modified ZnO nanoparticles were discussed. The self-assembly mechanism of the modified ZnO nanoparticles on the oil/water interface was suggested. The effect of dosage and size of the modified ZnO nanoparticles on miniemulsion stability and polymerization was researched. The nanospheres with the specific ZnO@PNIPAM structure and good dispersibility could be successfully prepared by the inverse Pickering miniemulsion method. The extracted ZnO@PNIPAM nanospheres simultaneously exhibited strong ultraviolet-visible absorption characteristics and luminescence intensity.