Soft nanoconfinement of ionic liquids in lyotropic liquid crystals.

Nanoconfinement of ionic liquids (ILs) influences their physicochemical properties. In this study, we investigate the effect of soft nanoconfinement imposed by lyotropic liquid crystals (LLCs) on ILs. The LLC ion gels are obtained through self-assembly of a short chain block copolymer (BCP) of polyethylene-block-poly(ethylene oxide), PE-b-PEO, in ILs. The effect of confinement on the interaction of ions with PEO is investigated through electrochemical impedance spectroscopy (EIS) and carbon dioxide (CO2) absorption measurements. The results show that the synergistic effect on the CO2 absorption capacity of LLC ion gels takes place as a result of confinement. Formation of IL pathways through the LLC increases the CO2 solubility, absorption capacity, and absorption rate. Increasing the concentration of block copolymer in the LLC structure enhances the dissociation of ILs and consequently lowers CO2 absorption. Therefore, the competing effects of confinement and IL-PEO interaction control the properties of LLC ion gels.

Formation of ion gels by polymerization of block copolymer/ionic liquid/oil mesophases.

In this study, we introduce a new method of developing ion gels through polymerization of lyotropic liquid crystal (LLC) templates of monomer (styrene), cross-linker (divinylbenzene), ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate), and amphiphilic block copolymers (Pluronic F127). The polymerization of the oil phase boosts the mechanical properties of the ion-conducting electrolytes. We discuss the effect of tortuosity induced by crystalline domains and LLC structure on the conductivity of ion gels. The ion transport in polymerized LLCs (polyLLCs) can be controlled by changing the composition of the mesophases. Increasing the block copolymer concentration enhances the crystallinity of PEO blocks in the conductive domains, which slows down the dynamics of PEO chain and ion transport. We show that by adjusting the composition of LLC mesophases, the mechanical strength of ion gels can be increased one order of magnitude without compromising the ionic conductivity. The polyLLCs with 45/25/30 wt% (block copolymer/IL/oil) composition has storage modulus and ionic conductivity higher than 1 MPa and 3 mS cm-1 at 70 °C, respectively. The results suggest that LLC templating is a promising method to develop highly conductive ion gels, which provides advantages in terms of variety and processing.

Pore-size-dependent calcium carbonate precipitation controlled by surface chemistry.

Induced mineral precipitation is potentially important for the remediation of contaminants, such as during mineral trapping during carbon or toxic metal sequestration. The prediction of precipitation reactions is complicated by the porous nature of rocks and soils and their interaction with the precipitate, introducing transport and confinement effects. Here X-ray scattering measurements, modeling, and electron microscopies were used to measure the kinetics of calcium carbonate precipitation in a porous amorphous silica (CPG) that contained two discrete distributions of pore sizes: nanopores and macropores. To examine the role of the favorability of interaction between the substrate and precipitate, some of the CPG was functionalized with a self-assembled monolayer (SAM) similar to those known to enhance nucleation densities on planar substrates. Precipitation was found to occur exclusively in macropores in the native CPG, while simultaneous precipitation in nanopores and macropores was observed in the functionalized CPG. The rate of precipitation in the nanopores estimated from the model of the X-ray scattering matched that measured on calcite single crystals. These results suggest that the pore-size distribution in which a precipitation reaction preferentially occurs depends on the favorability of interaction between substrate and precipitate, something not considered in most studies of precipitation in porous media.

High-pressure cell for neutron reflectometry of supercritical and subcritical fluids at solid interfaces.

A new high-pressure cell design for use in neutron reflectometry (NR) for pressures up to 50 MPa and a temperature range of 300-473 K is described. The cell design guides the neutron beam through the working crystal without passing through additional windows or the bulk fluid, which provides for a high neutron transmission, low scattering background, and low beam distortion. The o-ring seal is suitable for a wide range of subcritical and supercritical fluids and ensures high chemical and pressure stability. Wafers with a diameter of 5.08 cm (2 in.) and 5 mm or 10 mm thickness can be used with the cells, depending on the required pressure and momentum transfer range. The fluid volume in the sample cell is very small at about 0.1 ml, which minimizes scattering background and stored energy. The cell design and pressure setup for measurements with supercritical fluids are described. NR data are shown for silicon/silicon oxide and quartz wafers measured against air and subsequently within the high-pressure cell to demonstrate the neutron characteristics of the high-pressure cell. Neutron reflectivity data for supercritical CO(2) in contact with quartz and Si/SiO(2) wafers are also shown.

Characteristics of outpatients with COPD in daily practice: The E4 Spanish project.

The objective of this 1-week cross-sectional survey was to assess the clinical features of outpatients with chronic obstructive pulmonary disease (COPD). A one-page questionnaire was used to collect demographic data, smoking status, and COPD-related variables. Ten or 20 consecutive patients were selected from Primary care or specialised setting during a week. Pulmonary function (FEV1) was measured using an electronic device (Piko-1). The study sample comprised 11,973 COPD patients (83% men) with a mean (sd) age of 67 (10.7) years. Thirty-five percent of patients were current smokers and smoked a mean of 17.4 (9.9) cigarettes daily. COPD severity according to GOLD stages was mild in 20% of patients, moderate in 38%, severe in 30%, and very severe in 12%. A higher percentage of men showed severe (33%) or very severe (14%) disease compared to women (16% and 6%, respectively) (P<0.005). Forty-two percent of patients had severe functional impairment and 35% continued smoking. Moreover, 11% of patients with very severe COPD smoked more than 20 cigarettes a day. The mean frequency of visits in the previous year was every 4.6 (4.1) months, with cough as the main reason for consultation. The most commonly used drugs were long-acting beta2-agonists (78%) and inhaled steroids (77%). Inhaled steroids were used by 84% of patients with very severe, 82% with severe disease, 73% with moderate disease, and 69% with mild disease (chi2 for trend, P<0.0001). This survey carried out in a real life setting shows that 42% of the patients who completed the questionnaire had severe COPD, 35% of them continued smoking, and 69% of patients with mild COPD used inhaled steroids.