title: Unconventional assembly of bimetallic Au-Ni janus nanoparticles on chemically modified silica spheres.
abstract: This paper reports that Janus Au-Ni nanoparticles (JANNPs) can self-assemble onto silica spheres in a novel way, which is different from that of single-component isotropic nanoparticles. JANNPs modified with octadecylamine (ODA) assemble onto catechol-modified silica spheres (SiO2-OH) to form a very special core-loop complex structure and finally the core-loop assemblies link each other to form large assemblies through capillary force and the hydrophobic interaction of the alkyl chains of ODA. The nanocomposites disassemble in the presence of vanillin and oleic acid because of the breakage of the catechol-metal link. Vanillin-induced disassembly enables the JANNPs to reassemble into a core-loop structure upon ODA addition. The assembly of SiO2-OH and isotropic Ni or Fe3O4 particles generates traditional core-satellite structures. This unconventional self-assembly can be attributed to the synergistic effect of Janus specificity and capillary force, which is also confirmed by the assembly of thiol-terminated silica spheres (SH-SiO2) with anisotropic JANNPs, isotropic Au, and Ni nanoparticles. These results can guide the development of novel composite materials using Janus nanoparticles as the primary building blocks.
authors.affiliation: State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Department of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China).
authors.forename: Lei
authors.initials: L
authors.lastname: Jia
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Pei
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.forename: Weimin
authors.initials: W
authors.lastname: Liu
mesh_terms: D000588:Amines / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure*; D009532:Nickel / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D000588:Amines; D006046:Gold; D012822:Silicon Dioxide; D009532:Nickel; C009317:stearylamine
keywords: nanoparticles; reassembly; self-assembly; silica nanospheres; synergistic effects