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L-Cys-modified Fe3O4 was first prepared by a one-step partially-reduced method under mild conditions. Then, novel pine cone-like Fe3O4@Cu2O/Cu nanocomposites (NCs) with photomagnetic difunction were successfully synthesized via a one-pot solvothermal method on Fe3O4 without any additional linker or reducer. The average diameter of the as-synthesized products was about 4 μm, and the products were orderly assembled into many sheets with an average thickness of ~100 nm, possessing a porous structure. A possible formation mechanism of Fe3O4@Cu2O/Cu NCs involving interfacial recognization of ions, nucleation, aggregation, in situ transformation from Cu2O to Cu and Ostwald ripening process is proposed. The pine cone-like porous composites show excellent photocatalytic activity such that MO degradation efficiency is about 96% at an irradiation time of 20 min under visible light. Also, the composites present higher stability than Fe3O4@Cu2O and do not exhibit any significant loss after five recycles for the photodegradation of MO. The above results demonstrate that Cu could improve the photocatalytic activity of NCs and also inhibit the photocorrosion behavior of NCs. These novel Fe3O4@Cu2O/Cu composite materials are ideal candidates in water treatment and environmental cleaning as well as in magnetic applications, etc.

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In this study, secondary nucleation in emulsion polymerization of butyl acrylate (BA), styrene (St), and 2-hydroxyethyl methacrylate (HEMA), was investigated. Different molar ratios of BA and St were used. Average particle size, particle size distribution (PSD), polymerization kinetics, glass transition temperature (T g), and surface tension were monitored and compared. All synthetic latexes were prepared through seeded semi-batch emulsion polymerization process. Three different BA to St ratios (1:1, 1:2, 2:1) were combined with eight different HEMA contents (0, 1, 3, 5, 10, 20, 30, 40 mol%) in monomer composition, respectively. In the case of high HEMA content (10-40 mol%) it is found that secondary nucleation is mainly affected by HEMA. Secondary nucleation at low HEMA content (1-5 mol%) is dependent on the BA to St monomer ratio, and consequently a reflection of z-mer hydrophobicity.

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