Controlling Microstructure-Transport Interplay in Poly(ether--amide) Multiblock Copolymer Gas Separation Membranes.

In this study, we investigated the effect of morphology on the gas-transport properties of a poly(ether--amide) (PEBA) multiblock copolymer. We annealed the copolymer samples and varied the annealing temperature to evaluate the influence of changes in the microstructure on the gas transport properties of PEBA. In addition, we used time-resolved attenuated total reflection Fourier transform infrared spectroscopy to evaluate the diffusion coefficient of CO in PEBA based on the Fickian model.

Cellulose Nanocrystals Crosslinked with Sulfosuccinic Acid as Sustainable Proton Exchange Membranes for Electrochemical Energy Applications.

Nanocellulose is a sustainable material which holds promise for many energy-related applications. Here, nanocrystalline cellulose is used to prepare proton exchange membranes (PEMs). Normally, this nanomaterial is highly dispersible in water, preventing its use as an ionomer in many electrochemical applications.

"Artificial Wood" Lignocellulosic Membranes: Influence of Kraft Lignin on the Properties and Gas Transport in Tunicate-Based Nanocellulose Composites.

Nanocellulose membranes based on tunicate-derived cellulose nanofibers, starch, and ~5% wood-derived lignin were investigated using three different types of lignin. The addition of lignin into cellulose membranes increased the specific surface area (from 5 to ~50 m/g), however the fine porous geometry of the nanocellulose with characteristic pores below 10 nm in diameter remained similar for all membranes. The permeation of H, CO, N, and O through the membranes was investigated and a characteristic Knudsen diffusion through the membranes was observed at a rate proportional to the inverse of their molecular sizes.

Critical Role of the Molecular Interface in Double-Layered Pebax-1657/PDMS Nanomembranes for Highly Efficient CO/N Gas Separation.

In this work, we deposited a CO-selective block copolymer, Pebax-1657, as a selective layer with a thickness of 2-20 nm on the oxygen plasma-activated surface of poly(dimethylsiloxane) (PDMS) used as a gutter layer (thickness ∼400 nm). This double-layered structure was subsequently transferred onto the polyacrylonitrile (PAN) microporous support and studied for CO/N separation. The effect of interfacial molecular arrangements between the selective and gutter layers on CO permeance and selectivity has been investigated.

Study of Gases Permeation in Necklace-Shaped Dimethylsiloxane Polymers Bearing POSS Cages.

The transport of small gases (H, CO, N, O) through a series of novel membranes based on necklace-shaped inorganic polymers (DMS@POSS), in which a polyhedral oligomeric silsesquioxane (POSS) cage unit and soft chains of oligo-dimethyl siloxane (DMS) were alternately connected, was investigated. The influence of the DMS chain length and crosslinking density of the DMS@POSS on membrane properties were studied. The membranes revealed characteristic structure-property relation towards both glass transition and gases transport.

Thickness Effect on CO₂/N₂ Separation in Double Layer Pebax-1657/PDMS Membranes.

The effect of thickness in multilayer thin-film composite membranes on gas permeation has received little attention to date, and the gas permeances of the organic polymer membranes are believed to increase by membrane thinning. Moreover, the performance of defect-free layers with known gas permeability can be effectively described using the classical resistance in series models to predict both permeance and selectivity of the composite membrane. In this work, we have investigated the Pebax-MH1657/PDMS double layer membrane as a selective/gutter layer combination that has the potential to achieve sufficient CO₂/N₂ selectivity and permeance for efficient CO₂ and N₂ separation.

Characterization of polymer-polymer type charge-transfer (CT) blend membranes for fuel cell application.

The data presented in this article are related to polymer-polymer type charge-transfer blend membranes for fuel cell application. The visible spectra of the charge-transfer (CT) blend membranes indicated formation of CT complex in the blend membranes, and behavior of CT complex formation by polymers was clarified by Job plot of the visible spectra. The effect of fluorine for membrane property and fuel cell performance of CT blend membranes were evaluated by F NMR and overvoltage analysis, respectively.

Membrane thinning for efficient CO capture.

Enhancing the fluxes in gas separation membranes is required for utilizing the membranes on a mass scale for CO capture. Membrane thinning is one of the most promising approaches to achieve high fluxes. In addition, sophisticated molecular transport across membranes can boost gas separation performance.

Macroscale Superlubricity of Multilayer Polyethylenimine/Graphene Oxide Coatings in Different Gas Environments.

Friction and wear decrease the efficiency and lifetimes of mechanical devices. Solving this problem will potentially lead to a significant reduction in global energy consumption. We show that multilayer polyethylenimine/graphene oxide thin films, prepared via a highly scalable layer-by-layer (LbL) deposition technique, can be used as solid lubricants.

A Nano-Thin Film-Based Prototype QCM Sensor Array for Monitoring Human Breath and Respiratory Patterns.

Quartz crystal microbalance (QCM) sensor array was developed for multi-purpose human respiration assessment. The sensor system was designed to provide feedback for human respiration. Thorough optimization of measurement conditions: air flow, temperature in the QCM chamber, frequency measurement rate, and electrode position regarding to the gas flow-was performed.

In vitro detection of small molecule metabolites excreted from cancer cells using a Tenax TA thin-film microextraction device.

We developed a new device for the in vitro extraction of small molecule metabolites excreted from cancer cells. The extraction device, which was biocompatible and incubated with cancer cells, consists of a thin Tenax TA film deposited on the surface of a cylindrical aluminum rod. The Tenax TA solid phase was utilized for the direct extraction and preconcentration of the small molecule metabolites from a cell culture sample.

Titania nanocoating on MnCO3 microspheres via liquid-phase deposition for fabrication of template-assisted core-shell- and hollow-structured composites.

A novel class of core-shell- and hollow-structured MnCO3/TiO2 composites was synthesized by titania nanocoating on MnCO3 microspheres via two-step liquid-phase deposition at room temperature. Morphological change from core-shell to hollow microparticles was possible in the prepared samples by controlling prereaction time of MnCO3 and [NH4]2TiF6. Upon the prereaction process, the core of the core-shell MnCO3/TiO2 became highly porous, and a honeycomb-like surface that resembled the orientation of self-assembled MnCO3 nanocrystals was developed.

Self-assembly and imprinting of macrocyclic molecules in layer-by-layered TiO2 ultrathin films.

Alternate TiO2 gel ultrathin films assembled with a macrocyclic carboxylic acids of tetrakis-4-carboxyphenyl porphine (TCPP) or tetra-4-carboxylphthalocyanine cobalt (II) (Co-TCPc) were prepared by the surface sol-gel process. To confirm the film growth and imprinting effect, quartz crystal microbalance (QCM) and UV-vis spectroscopy measurements were employed. The binding of TCPP was 1.

TD-GC-MS Investigation of the VOCs Released from Blood Plasma of Dogs with Cancer.

An analytical TD-GC-MS method was developed and used for the assessment of volatile organic compounds (VOCs) released from the blood plasma of dogs with/without cancer. VOCs released from 40 samples of diseased blood and 10 control samples were compared in order to examine the difference between both sample groups that were showing qualitatively similar results independent from the disease's presence. However, mild disturbances in the spectra of dogs with cancer in comparison with the control group were observed, and six peaks (tentatively identified by comparison with mass spectral library as hexanal, octanal, toluene, 2-butanone, 1-octen-3-ol and pyrrole) revealed statistically significant differences between both sample groups, thereby suggesting that these compounds are potential biomarkers that can be used for cancer diagnosis based on the blood plasma TD-GC-MS analysis.

Respiratory monitoring by porphyrin modified quartz crystal microbalance sensors.

A respiratory monitoring system based on a quartz crystal microbalance (QCM) sensor with a functional film was designed and investigated. Porphyrins 5,10,15,20-tetrakis-(4-sulfophenyl)-21H,23H-porphine (TSPP) and 5,10,15,20-tetrakis-(4-sulfophenyl)-21H, 23H-porphine manganese (III) chloride (MnTSPP) used as sensitive elements were assembled with a poly(diallyldimethyl ammonium chloride) (PDDA). Films were deposited on the QCM resonators using layer-by-layer method in order to develop the sensor.

Remarkable enantioselectivity of molecularly imprinted TiO2 nano-thin films.

TiO(2) nano-thin films with imprinted (R)- and (S)-enantiomers of propranolol, 1,1'-bi-naphthol, and 2-(4-isobutylphenyl)-propionic acid were fabricated on quartz plates by spin-coating their solutions with Ti(O-(n)Bu)(4) in a toluene-ethanol mixture (1:1, v/v). After template removal, the imprinted films showed better binding for original templates than to the corresponding enantiomers. The assessment of template incorporation, template removal, and re-binding was conducted through UV-vis measurements.

Simultaneous monitoring of humidity and chemical changes using quartz crystal microbalance sensors modified with nano-thin films.

Quartz crystal microbalance (QCM) electrodes modified with nano-thin films were used to develop a system for measuring significant environment changes (smoke, humidity, hazardous material release). A layer-by-layer approach was used for the deposition of sensitive coatings with a nanometer thickness on the electrode surface. The QCM electrode was modified with self-assembled alternate layers of tetrakis-(4-sulfophenyl) porphine (TSPP) (or its manganese derivative, MnTSPP) and poly(diallyldimethylammonium chloride) (PDDA).