On-surface synthesis of extended linear graphyne molecular wires by protecting the alkynyl group.

In this paper we report on the use of an Ullmann-like aryl halide homocoupling reaction to obtain long Graphyne Molecular Wires (GY MWs) organized in dense, ordered arrays. Instead of using highly reactive terminal alkynes, we resort to a precursor wherein the acetylenic functional group is internal, namely protected by two phenyl rings, each bearing a Br atom in the para position to allow for linear homocoupling. In addition, two further factors concur with the production of dense and highly ordered arrays of very long GY MWs, namely the geometric compatibility between the substrate and both the organometallic intermediates and the final polymeric products of the synthesis, coupled with the presence of surface-adsorbed bromine atoms separating the MWs, which minimize inter-wire cross-linking secondary reactions.

Adsorption of Polylactic-co-Glycolic Acid on Zinc Oxide Systems: A Computational Approach to Describe Surface Phenomena.

Zinc oxide and polylactic-co-glycolic acid (ZnO-PLGA) nanocomposites are known to exhibit different biomedical applications and antibacterial activity, which could be beneficial for adding to wound dressings after different surgeries. However, possible cytotoxic effects along with various unexpected activities could reduce the use of these prominent systems. This is correlated to the property of ZnO, which exhibits different polymeric forms, in particular, wurtzite, zinc-blende, and rocksalt. In this study, we propose a computational approach based on the density functional theory to investigate the properties of ZnO-PLGA systems in detail. First, three different stable polymorphs of ZnO were considered. Subsequently, the abilities of each system to absorb the PLGA copolymer were thoroughly investigated, taking into account the modulation of electrical, optical, and mechanical properties. Significant differences between ZnO and PLGA systems have been found; in this study, we remark on the potential use of these models and the necessity to describe crucial surface aspects that might be challenging to observe with experimental approaches but which can modulate the performance of nanocomposites.

Substrate involvement in dioxygen bond dissociation catalysed by iron phthalocyanine supported on Ag(100).

Dioxygen adsorbs in the end-on configuration on-top of the Fe atoms of an iron phthalocyanine monolayer supported on Ag(100) and is partly cleaved at room temperature to produce O/FePc/Ag(100). Scanning tunnelling microscopy coupled to density functional theory calculations gives the first experimental evidence of the substrate involvement in the O2 bond dissociation.

Size-dependent characteristics of electrostatically actuated fluid-conveying carbon nanotubes based on modified couple stress theory.

The paper presents the effects of fluid flow on the static and dynamic properties of carbon nanotubes that convey a viscous fluid. The mathematical model is based on the modified couple stress theory. The effects of various fluid parameters and boundary conditions on the pull-in voltages are investigated in detail. The applicability of the proposed system as nanovalves or nanosensors in nanoscale fluidic systems is elaborated. The results confirm that the nanoscale system studied in this paper can be properly applied for these purposes.