Search

PS-b-PAA/copper composite two-dimensional nanoflowers with highly heterogeneous catalytic activity and good stability was fabricated at the liquid/liquid interface. To design and prepare heterogeneous catalysts with both high catalytic activity and good stability is still a challenge. Herein, we fabricated a composite Cu/PS-b-PAA film consisting of unique nanoflowers for the heterogeneous catalytic reactions such as hydrogenation of nitroarenes in aqueous solutions at the planar liquid/liquid interface through the interfacial adsorption and self-assembly process. The nanoflowers are comprised of nanoplates with a thickness of about 10 nm. The nanoplates have layered structure composed of an inner layer of hydrophobic PS and two surface layers of hydrophilic PAA where the copper species are dispersed. The composite film exhibited high catalytic activity for the reduction of p -nitroaniline (p -NA) in aqueous solutions and the rate constant reached to 396.45 s−1 g−1. Inaddition, the composite film also showed good stability and high recyclability without any changes in the rate constant and conversion efficiency in 15 successive cycles. These should be attributed to the special structure of the composite nanoflowers. We developed an excellent heterogeneous catalyst system possessed of both high activity and good stability through delicate design and fabrication. [ABSTRACT FROM AUTHOR]

Composite nanostructures of PS-b-PAA/Mn+ with various morphologies were fabricated in solutions, emulsions and at interfaces. • A DMF−CHCl 3 solution of PS-b-PAA/aqueous solution of salt interface was constructed. • O/W and W/O emulsions were generated through a spontaneous emulsification process. • PS-b-PAA self-assembled into various organized aggregates in these emulsions. • The molecular structure of PS-b-PAA greatly affects the self-assembly behavior. • The concentration and sort of the metal ions also affect the self-assembly behavior. Composite organized molecular assemblies of amphiphilic block copolymers exhibit various properties and functionalities and have attracted much attention recently. Many research studies have focused on adjusting these properties by varying the fabrication approach and by controlling the morphology of the aggregates. This work involved an investigation of the self-assembly behavior of a series of polystyrene-b-polyacrylic acid (PS-b-PAA) homologues with different block ratios in water-in-oil (W/O) and oil-in-water (O/W) emulsions. These emulsions simultaneously formed via a spontaneous emulsification process across the liquid/liquid interface. A variety of aggregates of the polymers with metal ions were obtained, including microcapsules, spherical micelles, rod-like and disc-like micelles, vesicles, and interior microphase-separated particles. These structures formed either in the emulsion droplets or in the continuous phase, and then proceeded to adsorb at the air/liquid interface or the planar liquid/liquid interface to form thin films. The influence of the molecular structure, the concentration of the metal ions, and the nature of the metal ion on the self-assembly behavior of the polymer molecules and the aggregate morphologies is discussed. In addition, these composite structures are shown to exhibit higher catalytic activity and good stability for the hydrogenation of nitroarenes in aqueous solutions. [ABSTRACT FROM AUTHOR]