Modulated self-assembly of 4,4'-diphenyltetrathiafulvalene molecules on highly oriented pyrolytic graphite by n-tetradecane solvent.

We report the formation of a binary-component self-assembled monolayer (SAM) comprising 4,4'-diphenyltetrathiafulvalene (DP-TTF) and n-tetradecane (n-C(14)H(30)) molecules with periodic strip-like phase separation structures on a highly oriented pyrolytic graphite (HOPG) surface. Scanning tunneling microscopy (STM) imaging reveals that ordered DP-TTF single- and double-lamella are periodically tuned by ordered n- C(14)H(30) single- and double-lamella, respectively. This finding can be qualitatively understood in terms of a phase field model, in which the interplay of three ingredients, including free energy of the binary-component solution monolayer, phase boundary energy and surface stress, determines the final equilibrium sizes of the ordered DP-TTF and n- C(14)H(30) phases in the binary-component SAM.

The shape evolution of gold seeds and gold@silver core-shell nanostructures.

We report the seed-dependent shape evolution of gold@silver (Au@Ag) core-shell nanostructures with various morphologies through using pre-existing Au nanocrystals as nuclei in a polyvinylpyrrolidone (PVP)-assisted polyol reduction process. Au nanocrystalline seeds with different shapes such as cube, truncated-octahedron, octahedron, twinned hexagon and triangle, five-twinned decahedron and nanorod are firstly synthesized by refluxing a 1,5-pentanediol solution containing Au precursors in the presence of PVP. The Au seeds obtained in this way then serve as the nuclei for further epitaxial growth of Ag shells by using Ag precursors via the same route.

STM imaging ortho- and para-fluorothiophenol self-assembled monolayers on Au(111).

Self-assembled monolayers (SAMs) of para- and ortho-fluorothiophenol (p- and o-FTP) spontaneously formed on Au(111) substrate have been contrasted through investigation by a scanning tunneling microscope (STM) at room temperature. High-resolution STM imaging reveals that p-FTP adopts a 6 x radical3R30 degrees molecule arrangement containing six molecules. Two different kinds of p-FTP molecule dimer line structures have been formed on Au(111) by intermolecular pi-pi stacking along 112 substrate directions, besides a single p-FTP molecule line.

Poly(N-vinyl-2-pyrrolidone) (PVP)-capped dendritic gold nanoparticles by a one-step hydrothermal route and their high SERS effect.

Dendritic gold (Au) nanoparticles have been successfully synthesized by the one-step hydrothermal reduction of HAuCl4.4H2O using ammonium formate (AF) as a reducing agent in the presence of PVP. Effects of different reactant concentrations on the morphologies of obtained products have been systematically investigated.

[Importance of nanobiology and nanomedicine].

Focused on nanobiology and nanomedicine, this article elucidates its main research targets and contents, discusses the important of researches in this field, introduces the tasks and objectives of the corresponding researches in the national long- and mid-term science and technology development planning, and also describes the present research status in China.

Poly(vinyl pyrrolidone)-capped five-fold twinned gold particles with sizes from nanometres to micrometres.

Poly(vinyl pyrrolidone)-capped multiple twinned gold (Au) particles with decahedral shape have been synthesized by a simple and convenient solvothermal wet chemical method. In the process, hydrogen tetrachloroauric acid (HAuCl(4).3H(2)O) was reduced by ethylene glycol (EG) to form the multiple twinned Au nanocrystals in the presence of poly(vinyl pyrrolidone) (PVP) molecules at 200 degrees C under the extra condition of autogenous pressure.

Machinable long PVP-stabilized silver nanowires.

PVP-capped silver nanowires with a diameter range from 150 to 200 nm and a length range from 50 to 100 microm have been synthesized in large quantity by using a soft-template liquid-phase method. The so-obtained longer and thicker metallic nanowires exhibit fivefold-twinned structures bound by five [1 0 0] wall-planes and two spearlike ends around five [1 1 1] facets. X-ray photoelectron spectroscopy (XPS) investigations show that a strong interaction exists between the carboxyl oxygen atom (C=O) of PVP and the Ag core interface.