An extremely simple and effective strategy to tailor the surface performance of inorganic substrates by two new photochemical reactions

This article reports on a new sequential strategy to fabricate monolayer functional organosilane films on inorganic substrate surfaces, and subsequently, to pattern them by two new photochemical reactions. (1) By using UV light (254 nm) plus dimethylformamide (DMF), a functional silane monolayer film could be fabricated quickly (within minutes) under ambient temperature. (2) The organic groups of the formed films became decomposed in a few minutes with UV irradiation coupled with a water solution of ammonium persulfate (APS). (3) When two photochemical reactions were sequentially combined, a high-quality patterned functional surface could be obtained thanks to the photomask.

Two-dimensional polymer as a mask for surface nanopatterning

NaCl islands are used as a sacrificial layer to selectively deposit a boronic acid based two-dimensional polymer. The nanostructured polymer layer can be used as a negative mask to create Fe islands in a nanolithography mimicking process.

Hierarchical structures of ZnO spherical particles synthesized solvothermally

We review the solvothermal synthesis, using a mixture of ethylene glycol (EG) and water as the solvent, of zinc oxide (ZnO) particles having spherical and flower-like shapes and hierarchical nanostructures. The preparation conditions of the ZnO particles and the microscopic characterization of the morphology are summarized. We found the following three effects of the ratio of EG to water on the formation of hierarchical structures: (i) EG restricts the growth of ZnO microcrystals, (ii) EG promotes the self-assembly of small crystallites into spheroidal particles and (iii) the high water content of EG results in hollow spheres.

Aqueous solution synthesis of SnO nanostructures with tuned optical absorption behavior and photoelectrochemical properties through morphological evolution

We have studied the aqueous solution synthesis of divalent tin oxide (SnO) nanostructures, changes in their optical absorption behavior, and their photoelectrochemical properties. A number of SnO nanostructures including sheets and wires, and their composite morphologies were obtained in aqueous solution containing urea at low temperatures. Parallel control of both oxidation state and morphology was achieved through the urea-mediated solution process. Nanoscale morphological variation facilitated changes in optical absorption behavior and the generation of a photocurrent. As for the nanostructured SnO, the absorption of visible light decreased and absorption in UV region increased. In contrast, bulk black SnO crystals showed strong absorption over the entire range of UV to visible light. A photocurrent was generated from the SnO nanostructures with irradiation of UV and visible light.

Nanosegregated composites of an imidazolium salt and a layered inorganic compound: organization of both anions and cations in interlayer space

The organization of an imidazolium salt in the interlayer space of a layered inorganic compound leads to the formation of nanosegregated composites.

Bioinspired synthesis of continuous titania coat with tunable nanofiber-based network structure on linear polyethylenimine-covered substrates

We report using the substrates covered with self-organized linear polyethylenimine (PEI) layer as biomimetic template to direct the formation of high-quality titania coat with well-defined nanofiber-based network structure. The titania deposition was simply achieved by dipping the PEI substrates into aqueous solution of titanium bislactate under ambient conditions. We found that crystalline PEI layer on the substrates is important for achieving titania coat with nanofiber-based structure. Compared to the titania powder formed by solution deposition, the interface-mediated nanostructured titania exhibited dramatically improved thermostability with being able to maintain anatase phase in majority even at 900 degrees C. Moreover, the nanostructures of titania coat could be well controlled by simply adjusting the formation conditions of crystalline PEI layer on substrates. Because of high-efficiency photocatalysis of anatase titania, the nanostructured surface exhibited good photoresponsive surface wettability through hydrophobic modification and light irradiation.

Atomic force microscope nanolithography: dip-pen, nanoshaving, nanografting, tapping mode, electrochemical and thermal nanolithography

Atomic force microscopy (AFM) has been widely employed as a nanoscopic lithography technique. In this review, we summarize the current state of research in this field. We introduce the various forms of the technique, such as nanoshaving, nanografting and dip-pen nanolithography, which we classify according to the different interactions between the AFM probe and the substrate during the nanolithography fabrication process. Mechanical force, applied by the tip to the substrate, is the variable that can be controlled with good precision in AFM and it has been utilized in patterning self-assembled monolayers. In such applications, the AFM tip can break some relatively weak chemical bonds inside the monolayer. In general, the state of the art for AFM nanolithography demonstrates the power, resolution and versatility of the technique.