Mechanically polished copper surfaces modified with n-dodecanethiol and 3-perfluorooctyl-propanethiol

A facile strategy to decorate Cu₉S₅ nanocrystals on polyaniline nanowires and their synergetic catalytic properties

Here, we demonstrated a novel method to decorate Cu₉S₅ nanocrystals on polyaniline (PANI) nanowires using the dopant of mercaptoacetic acid (MAA) in the PANI matrix as the sulfur source under a hydrothermal reaction. TEM images showed that Cu₉S₅ nanocrystals with a size in the range of 5-20 nm were uniformly formed on the surface of PANI nanowires. Significantly, the as-prepared PANI/Cu₉S₅ composite nanowires have been proven to be novel peroxidase mimics toward the oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H₂O₂. Due to the synergetic effects between polyaniline nanowires and Cu₉S₅ nanocrystals, the obtained PANI/Cu₉S₅ composite nanowires exhibit superior catalytic activity over the independent components. This work not only presents a simple and versatile method to decorate semiconductor nanocrystals on the surface of conducting polymer nanostructures, but also provides fundamental guidelines for further investigations into the synergetic effect between conducting polymers and other materials.

Highly efficient visible light photocatalysis of novel CuS/ZnO heterostructure nanowire arrays

Here, a facile approach for the fabrication of CuS nanoparticle (NP)/ZnO nanowire (NW) heterostructures on a mesh substrate through a simple two-step solution method is demonstrated. Successive ionic layer adsorption and reaction (SILAR) was employed to uniformly deposit CuS NPs on the hydrothermally grown ZnO NW array. The synthesized CuS/ZnO heterostructure NWs exhibited superior photocatalytic activity under visible light compared to bare ZnO NWs. This strong photocatalytic activity under visible light is due to the interfacial charge transfer (IFCT) from the valence band of the ZnO NW to the CuS NP, which reduces CuS to Cu(2)S. After repeated cycles of photodecolorization of Acid Orange 7 (AO7), the photocatalytic behavior of CuS/ZnO heterostructure NWs exhibited no significant loss of activity. Furthermore, our CuS/ZnO NWs/mesh photocatalyst floats in solution via partial superhydrophobic modification of the NWs.

New semifluorinated dithiols self-assembled monolayers on a copper platform

New alpha,omega-semifluorinated dithiols HS-(CH2)11-(CF2)n-(CH2)11-SH, called DTn, and corresponding dithioacetate molecules CH3COS-(CH2)11-(CF2)n-(CH2)11-SCOCH3, called DTAn ( n = 4, 6, 8), were synthesized and used to create self-assembled monolayers (SAMs) on both untreated copper surfaces and electrochemically reduced ones. The aim of this study is to assess the organization of the resulting SAMs, particularly the effect of the presence of two perhydrogenated segments surrounding the perfluorinated one, and the ability of these difunctional molecules to bind copper substrates by only one end per molecule. In each case, the organization of the SAM is rather poor and only DTA8 molecules seem to adopt an upright position on reduced copper. In addition, the layers have been investigated by cyclic voltammetry (CV) to assess their coverage. DT4 SAMs reveal a covering ratio higher than 99%.

Silver hierarchical bowl-like array: synthesis, superhydrophobicity, and optical properties

We present a facile synthetic route to a silver bowl-like array film with hierarchical structures on glass substrate using the colloidal monolayer as a template. In these special hierarchical structures, microstructures were provided by a colloidal template of polystyrene latex spheres and nanostructures resulting from the thermal decomposition of silver acetate. These structures were chemically modified with 1-hexadecanethiol, and a corresponding self-assembled monolayer (SAM) was formed on their surfaces. Due to the lotus leaf-like morphology with hierarchical micro/nanostructures, the film displayed an extraordinary superhydrophobicity after chemical modification. Water contact angle and sliding angle were 169 degrees and 3 degrees (the weight of water droplets: 3 mg), respectively. Additionally, its optical property has also been investigated. This structure could be used in microfluidic devices, optical devices, and biological science.

Self-assembly of 1,4-phenylene diisocyanide and terephthalic acid on Ni, Cu and Pt

This paper compares the adsorption behavior of 1,4-phenylene diisocyanide (PDI) and terephthalic acid (TA) on Ni, Cu and Pt surfaces. Following competitive adsorption from two-component equimolar solutions of PDI and TA, chemical analysis by XPS confirmed the preferential adsorption of PDI over TA on Ni and Cu. The ability to form "chemically sticky" surfaces on Ni, Cu and Pt surfaces by self-assembly into organized organic thin films (OOTFs) was also investigated. PM-IRRAS analysis revealed a tendency for PDI to bond in a terminal fashion through one isocyanide group, on both Ni and Cu. In contrast, PDI adsorbed in a flat configuration on Pt. Chemically sticky OOTFs have potential for utilization as coupling agents to achieve a high cross-link density and enhance stress transfer between the nanoclusters and the organic matrix molecules in metal-nanocluster-filled polymer matrix nanocomposites. The results of this work indicate that 1,4-phenylene diisocyanide is a suitable choice as a coupling agent for metal nanoclusters of Ni and Cu.

Surface reactions of 1-propanethiol on GaAs(100)

The adsorption and decomposition pathways of 1-propanethiol on a Ga-rich GaAs(100) surface have been investigated using the techniques of temperature programmed desorption, X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (TOF-SIMS). 1-Propanethiol adsorbs dissociatively on a clean GaAs(100) surface to form propanethiolate and hydrogen. Further reactions of these species to form new products compete with the recombinative desorption of molecular propanethiol. The C-S bond scission in the propanethiolate results in the formation of propyl species and elemental sulfur. The generation of propene via beta-hydride elimination then follows. In addition, propane and hydrogen form via reductive elimination processes. A recombinative high-temperature propanethiol desorption state is also observed. XPS and TOF-SIMS analyses confirm the presence of sulfur on the GaAs(100) surface following thermal decomposition. This paper discusses the mechanisms by which these products form on the GaAs(100) surface.