This paper reports that Janus AuNi 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 (SiO₂OH) 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 SiO₂OH 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 (SHSiO₂) 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.

Electrochemically induced surface-initiated atom-transfer radical polymerization is traced by in situ AFM technology for the first time, which allows visualization of the polymer growth process. It affords a fundamental insight into the surface morphology and growth mechanism simultaneously. Using this technique, the polymerization kinetics of two model monomers were studied, namely the anionic 3-sulfopropyl methacrylate potassium salt (SPMA) and the cationic 2-(metharyloyloxy)ethyltrimethylammonium chloride (METAC). The growth of METAC is significantly improved by screening the ammonium cations by the addition of ionic liquid electrolyte in aqueous solution.

A new kind of initiator, 3-(2-bromo-2-methylacryloxy)propyltriethysiliane (MPTS-Br), was prepared with a simply hydrobrominated commercial silane coupling agent (3-methacryloxy-proplytriethysilane, MPTS). It has been one-step self-assemble onto the surface of attapulgite (ATP) nanorods in the dispersion system, and by using this initiator-modified nanorod (MPTS-Br-modified ATP nanoparticles, ATP-MPTS-Br) as macroinitiator for atom transfer radical polymerization (ATRP). Structurally well-defined homopolymer polystyrene (PS) and block polymer poly(styrene-b-methyl methacrylate) (PS-b-PMMA) chains were then grown from the needle-shaped nanorods surface to yield monodispersed nanorods composed of ATP core and thick-coated polymer shell (ATP and PS). The graft polymerization parameters exhibited the characteristics of a controlled/”living” polymerization. The PS-grafted ATP nanorods could be dispersed well in organic solvent with nanoscale. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The hydrophilicity of polytetrafluoroethylene (PTFE) micropowders was easily achieved by modifying the surface with thin polydopamine(Pdop) layer deposited through spontaneous oxidative polymerization of dopamine. Compared with the pure PTFE, the Pdop modified PTFE(PTFE@Pdop) possesses excellent hydrophilic property such as low active ratio, and good dispersivity in water. The quantity of coating and the surface amphiphilic properties were readily controlled by adjusting the deposition time. The tribological properties of the as-prepared PTFE@Pdop micropowders as additives in water were evaluated. The results confirmed that the PTFE@Pdop exhibited good antiwear and friction reduction properties even under low concentration in water. The simplicity of the method makes large-scale production of hydrophilic PTFE possible and may be extended as a powerful route for modification of other organic solid lubricating materials that can be exploited as water-based lubricant additives. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

The preparation of micropatterned TiO₂ nanotubes (NTs) with tunable morphologies by combining laser micromachining technology and an anodization method is reported. The micropatterned structure can be easily designed and fabricated by laser micromachining a titanium substrate, further anodization of which gives nanotube arrays perpendicularly oriented to the titanium surface. The patterned TiO₂ NTs show dramatically improved photocurrent and photocatalytic performances because of their enhanced surface area and light-harvesting capability. The photocurrent density and incident-photon-to-current efficiency at the peak absorption increases by 48 and 39%, respectively, compared to a TiO₂ NT array without a patterned structure. It was also found that micropatterning dramatically improves the mechanical stability of the TiO₂ NTs on the substrate, which otherwise were liable to peel off from the substrate surface. The strategy will reasonably expand the application of TiO₂ NTs in a variety of fields that require enhanced photo-electrocatalysis and mechanical stability.