Interfacial Growth of Large Area Single-Crystalline Silver Sheets Through Ambient Microdroplets.

The creation of micrometer-sized sheets of silver at the air-water interface by direct deposition of electrospray-generated silver ions (Ag) on an aqueous dispersion of reduced graphene oxide (RGO), in ambient conditions, is reported. In the process of electrospray deposition (ESD), an electrohydrodynamic flow is created in the aqueous dispersion, and the graphene sheets assemble, forming a thin film at the air-water interface. The deposited Ag coalesce to make single-crystalline Ag sheets on top of this assembled graphene layer.

Spontaneous α-C-H Carboxylation of Ketones by Gaseous CO at the Air-water Interface of Aqueous Microdroplets.

We present a catalyst-free route for the reduction of carbon dioxide integrated with the formation of a carbon-carbon bond at the air/water interface of negatively charged aqueous microdroplets, at ambient temperature. The reactions proceed through carbanion generation at the α-carbon of a ketone followed by nucleophilic addition to CO. Online mass spectrometry reveals that the product is an α-ketoacid.

Aggregation of molecules is controlled in microdroplets.

Molecular de-aggregation was observed at the air/water interface of aqueous microdroplets. We probed this phenomenon using dyes such as Rhodamine 6G (R6G), Rhodamine B, acridine orange, and fluorescein, which show aggregation-induced shift in fluorescence. The fluorescence micrographs of microdroplets derived from the aqueous solutions of these dyes show that they are monomeric at the air/water interface, but highly aggregated at the core.

2D-Molybdenum Disulfide-Derived Ion Source for Mass Spectrometry.

Generation of current or potential at nanostructures using appropriate stimuli is one of the futuristic methods of energy generation. We developed an ambient soft ionization method for mass spectrometry using 2D-MoS, termed streaming ionization, which eliminates the use of traditional energy sources needed for ion formation. The ionic dissociation-induced electrokinetic effect at the liquid-solid interface is the reason for energy generation.