SALDI-MS and SERS Multimodal Imaging: One Nanostructured Substrate to Rule Them Both.

Imaging techniques based on mass spectrometry or spectroscopy methods inform about the chemical composition of biological tissues or organisms, but they are sometimes limited by their specificity, sensitivity, or spatial resolution. Multimodal imaging addresses these limitations by combining several imaging modalities; however, measuring the same sample with the same preparation using multiple imaging techniques is still uncommon due to the incompatibility between substrates, sample preparation protocols, and data formats. We present a multimodal imaging approach that employs a gold-coated nanostructured silicon substrate to couple surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) and surface-enhanced Raman spectroscopy (SERS).

Lamellar nanoporous gold thin films with tunable porosity for ultrasensitive SERS detection in liquid and gas phase.

Lamellar nanoporous gold thin films, constituted of a stack of very thin layers of porous gold, are synthesized by chemical etching from a stack of successively deposited nanolayers of copper and gold. The gold ligament size, the pore size and the distance between lamellas are tunable in the few tens nanometer range by controlling the initial thickness of the layers and the etching time. The SERS activity of these lamellar porous gold films is characterized by their SERS responses after adsorption of probe bipyridine and naphtalenethiol molecules.

A Multiparameter Gas-Monitoring System Combining Functionalized and Non-Functionalized Microcantilevers.

The aim of the study is to develop a compact, robust and maintenance free gas concentration and humidity monitoring system for industrial use in the field of inert process gases. Our multiparameter gas-monitoring system prototype allows the simultaneous measurement of the fluid physical properties (density, viscosity) and water vapor content (at ppm level) under varying process conditions. This approach is enabled by the combination of functionalized and non-functionalized resonating microcantilevers in a single sensing platform.

Gas phase detection of chemical warfare agents CWAs with portable Raman.

The development of SERS substrates for chemical detection of specific analytes requires appropriate selection of plasmonic metal and the surface where it is deposited. Here we deposited Ag nanoplates on three substrates: i) conventional SiO/Si wafer, ii) stainless steel mesh and iii) graphite foils. The SERS enhancement of the signal was studied for Rhodamine 6 G (R6 G) as common liquid phase probe molecule.

Three-Dimensional Fractal Geometry for Gas Permeation in Microchannels.

The novel concept of a microfluidic chip with an integrated three-dimensional fractal geometry with nanopores, acting as a gas transport membrane, is presented. The method of engineering the 3D fractal structure is based on a combination of anisotropic etching of silicon and corner lithography. The permeation of oxygen and carbon dioxide through the fractal membrane is measured and validated theoretically.

Exploring the Gas-Permeation Properties of Proton-Conducting Membranes Based on Protic Imidazolium Ionic Liquids: Application in Natural Gas Processing.

This experimental study explores the potential of supported ionic liquid membranes (SILMs) based on protic imidazolium ionic liquids (ILs) and randomly nanoporous polybenzimidazole (PBI) supports for CH₄/N₂ separation. In particular, three classes of SILMs have been prepared by the infiltration of porous PBI membranes with different protic moieties: 1-H-3-methylimidazolium bis (trifluoromethane sulfonyl)imide; 1-H-3-vinylimidazolium bis(trifluoromethane sulfonyl)imide followed by in situ ultraviolet (UV) polymerization to poly[1-(3H-imidazolium)ethylene] bis(trifluoromethanesulfonyl)imide. The polymerization process has been monitored by Fourier transform infrared (FTIR) spectroscopy and the concentration of the protic entities in the SILMs has been evaluated by thermogravimetric analysis (TGA).

Hierarchical Porous Polybenzimidazole Microsieves: An Efficient Architecture for Anhydrous Proton Transport via Polyionic Liquids.

Liquid-induced phase-separation micromolding (LIPSμM) has been successfully used for manufacturing hierarchical porous polybenzimidazole (HPBI) microsieves (42-46% porosity, 30-40 μm thick) with a specific pore architecture (pattern of macropores: ∼9 μm in size, perforated, dispersed in a porous matrix with a 50-100 nm pore size). Using these microsieves, proton-exchange membranes were fabricated by the infiltration of a 1H-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide liquid and divinylbenzene (as a cross-linker), followed by in situ UV polymerization. Our approach relies on the separation of the ion conducting function from the structural support function.

Constructing Straight Polyionic Liquid Microchannels for Fast Anhydrous Proton Transport.

Polymeric ionic liquids (PILs) have triggered great interest as all solid-state flexible electrolytes because of safety and superior thermal, chemical, and electrochemical stability. It is of great importance to fabricate highly conductive electrolyte membranes capable to operate above 120 °C under anhydrous conditions and in the absence of mineral acids, without sacrificing the mechanical behavior. Herein, the diminished dimensional and mechanical stability of poly[1-(3H-imidazolium)ethylene]bis(trifluoromethanesulfonyl)imide has been improved thanks to its infiltration on a polybenzimidale (PBI) support with specific pore architecture.