MoVN-Cu Coatings for In Situ Tribocatalytic Formation of Carbon-Rich Tribofilms in Low-Viscosity Fuels.

Inhibiting the tribological failure of mechanical assemblies which rely on fuels for lubrication is an obstacle to maintaining the lifetime of these systems with low-viscosity and low-lubricity fuels. In the present study, a MoVN-Cu nanocomposite coating was tribologically evaluated for durability in high- and low-viscosity fuels as a function of temperature, load, and sliding velocity conditions. The results indicate that the MoVN-Cu coating is effective in decreasing wear and friction relative to an uncoated steel surface.

Salt Preform Texturing of Absorbable Zn Substrates for Bone-implant Applications.

Surface roughness is an important factor in improving the bone-implant contact area to enhance bone regeneration, yet this aspect has not been applied to absorbable metals. Textured zinc surfaces with varying degrees of surface roughness were produced using a salt-preform method with fine- and coarse-grained salts and compared to a polished control sample. The resulting surfaces were characterized by scanning electron microscopy (SEM), surface roughness, corrosion rates, and cytotoxicity.

Rapid Synthesis of Nanoporous Conformal Coatings via Plasma-Enhanced Sequential Infiltration of a Polymer Template.

Nanoporous conformal coating is an important class of materials for electrocatalysis, water purification, antireflective coatings, etc. Common synthesis methods of porous films often require harsh conditions (high temperature and high plasma power) or specific substrate materials. Here, we report a plasma-enhanced sequential infiltration synthesis (PE SIS) as a new platform toward deposition of nanoporous inorganic films.

(Ag,Cu)-Ta-O ternaries as high-temperature solid-lubricant coatings.

Ternary oxides have gained increasing attention due to their potential use as solid lubricants at elevated temperatures. In this work, the tribological properties of three ternary oxides-AgTaO3, CuTaO3, and CuTa2O6-were studied using a combination of density-functional theory (DFT), molecular dynamics (MD) simulations with newly developed empirical potential parameters, and experimental measurements (AgTaO3 and CuTa2O6 only). Our results show that the MD-predicted friction force follows the trend AgTaO3 < CuTaO3 < CuTa2O6, which is consistent with the experimentally measured coefficients of friction.

Investigating surface topology and cyclic-RGD peptide functionalization on vascular endothelialization.

The advantages of endothelialization of a stent surface in comparison with the bare metal and drug-eluting stents used today include reduced late-stent restenosis and in-stent thrombosis. In this article, we study the effect of surface topology and functionalization of tantalum (Ta) with cyclic-(arginine-glycine-aspartic acid-d-phenylalanine-lysine) (cRGDfK) on the attachment, spreading, and growth of vascular endothelial cells. Self-assembled nanodimpling on Ta surfaces was performed using a one-step electropolishing technique.

Carbon nanotube-MoS2 composites as solid lubricants.

Solid lubricants (SLs) characterized by low coefficients of friction (mu) and wear rates (w) drastically improve the life span of instruments that undergo extreme frictional wear. However, the performance of SLs such as sputtered or nanoparticulate molybdenum disulfide (MoS(2)), tungsten disulfide (WS(2)), or graphite deteriorates heavily under extreme operational conditions such as elevated temperatures and high humidity. Here, we present our preliminary results, which demonstrate that composites of carbon nanotubes (CNTs) and MoS(2) produced by electrodeposition of MoS(2) on vertically aligned CNT films have low mu ( approximately 0.

Synthesis and characterization of quantum dot-polymer composites.

In this study, we demonstrate a facile and simple synthesis of quantum dot (QD)-polymer composites. Highly fluorescent semiconducting CdSe/ZnS quantum dots were embedded in different commercially available polymers using one easy step. QD-polymer composite nanoparticles were also synthesized using template-assisted synthesis.

Synthesis and characterization of polydiacetylene films and nanotubes.

We report here the synthesis and characterization of polydiacetylene (PDA) films and nanotubes using layer-by-layer (LBL) chemistry. 10,12-Docosadiyndioic acid (DCDA) monomer was self-assembled on flat surfaces and inside of nanoporous alumina templates. UV irradiation of DCDA provided polymerized-DCDA (PDCDA) films and nanotubes.

Atomic scale interface engineering by modulated ion-assisted deposition applied to soft x-ray multilayer optics.

Cr/Sc and Ni/V multilayers, intended as normal incidence soft x-ray mirrors and Brewster angle polarizers, have been synthesized by employing a novel modulated low-energy and high-flux ion assistance as a means of engineering the interfaces between the subnanometer layers on an atomic scale during magnetron sputter deposition. To reduce both roughness and intermixing, the ion energy was modulated within each layer. The flat and abrupt interfaces yielded soft x-ray mirrors with near-normal incidence reflectances of R = 20.