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Ellipsoidal and spherical superstructures, network structure and hierarchical structure of noble metal spherical or rod-like nanoparticles were fabricated through a liquid/liquid interface mass transfer-assisted self-assembly process in aqueous solutions. • A general approach has been developed to fabricate superstructures of nanoparticles. • A liquid/liquid interface mass transfer process was used to introduce amines into hydrosols. • The fatty amines combined with colloidal particles and organized into superstructures. • Ellipsoidal and spherical superlattices of spherical nanoparticles were obtained. • Network and hierarchical structures of nanospheres and nanorods were obtained. Organized assemblies of noble metal nanoparticles (NPs) exhibit unique optical, electronic and catalytic properties and potential applications in various areas. Many kinds of methods have been developed to fabricate such functional systems. In this work, we report a facile and novel method to fabricate the organized aggregates of Au and Ag NPs. Their freshly prepared hydrosols were used as upper phase, and the DMF/chloroform solutions of different fatty amines were used as bottom phases to form a planar liquid/liquid interface. The mass transfer across the interface occurred immediately, where the DMF droplets containing fatty amines entered into the hydrosols, leading to the formation of organized aggregates of NPs through a self-assembly process of amine molecules. It was found that several kinds of assemblies were generated, including ellipsoidal and spherical superstructures of spherical NPs, networks of spherical NPs and nanorods, and hierarchical structure of nanorods. In addition, networks composed of Au NPs/Ag skeleton satellite-core type nanorods were further constructed, which exhibited good catalytic performance and SERS property. [ABSTRACT FROM AUTHOR]

Self-assembly behavior of amphiphilic block copolymers has attracted much attention recently. In this paper, a novel liquid/liquid interface-mediated self-assembly behavior of block copolymer is reported. An aqueous solution of HAuCl 4 and a chloroform solution of poly(2-vinylpyridine)- block -polycaprolactone (P2VP 199 -b-PCL 22) are employed as the upper phase and the bottom phase, respectively. Structural transitions from toroids and plate like structures to vesicles and large compound vesicles are observed in the bottom phase by using transmission electron microscopy (TEM). It is proved that vesicles and large compound vesicles are formed through adsorption and desorption of copolymers at the liquid/liquid interface, molecular aggregation and microphase separation in the bottom phase due to the amphiphilic property of protonated P2VP 199 -b-PCL 22. The well-dispersed Au nanoparticles are formed during the self-assembly process and embedded in the bilayers of the vesicles. The concentrations of HAuCl 4 and P2VP 199 -b-PCL 22 have an effect on the self-assembly behavior. A unique structure, "pearl necklace", is obtained at higher concentrations. In addition, it was found that P2VP 252 -b-PCL 44 also formed vesicles, while P2VP 195 -b-PCL 75 and P2VP 195 -b-PCL 307 formed spherical micelles in the bottom phase through the same approach. The dependence of the aggregate morphology and the molecular structure was discussed based on the critical packing parameter, p. Vesicles and large compound vesicles were generated through a liquid-liquid interface-mediated self-assembly process including adsorption, desorption, aggregation, and microphase separation steps. Unlabelled Image • Composite vesicles, compound vesicles and micelles of block copolymer/Au nanoparticles were generated. • These aggregates were formed through a liquid/liquid interface mediated process. • The block copolymer molecules adsorbed at the interface, combined with inorganic ions and returned to the organic phase. • The composite molecules formed aggregates in the organic phase through self-assembly and microphase separation. • The morphology of the aggregates depends on the critical packing parameters of the composite block copolymers. [ABSTRACT FROM AUTHOR]