Sorption and Diffusion of Gases in Liquid Crystalline Substances

Chen, Gong-Hao; Springer, Jürgen

doi:10.1080/10587250008031030

Cited by 15 publications

(10 citation statements)

References 15 publications

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“…The 10% difference between these two values might be caused by slight variations in the composition of the samples, as well as the different techniques used to determine the loading of the samples. The loadings obtained for this liquid crystalline system at 1 bar, are slightly higher than the values for three different thermotropic liquid crystals reported by Chen et al (MBBA, PCH5, and PCH8-CNS), where the highest loadings they measured were between 7–8 mg CO 2 /g liquid crystal [ 34 ].…”

Section: Resultscontrasting

confidence: 57%

CO2 in Lyotropic Liquid Crystals: Phase Equilibria Behavior and Rheology

et al. 2019

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The CO2 absorption of liquid crystalline phases of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (Pluronic L92, (EO)8(PO)47(EO)8), monoethanolamine (MEA), and water, with a composition of 60% L92/10% MEA/30% water has been investigated to assess potential use in carbon capture and storage applications. Vapor–liquid equilibrium data of the liquid crystalline system with CO2 was recorded up to a CO2 partial pressure of 6 bar, where a loading of 38.6 g CO2/kg sample was obtained. Moreover, the phase transitions occurring during the loading process were investigated by small angle X-ray scattering (SAXS), presenting a transition from lamellar + hexagonal phase to hexagonal (at 25 °C). In addition, the rheology of samples with varying loadings was also studied, showing that the viscosity increases with increasing CO2-loading until the phase transition to hexagonal phase is completed. Finally, thermal stability experiments were performed, and revealed that L92 does not contribute to MEA degradation.

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Section: Resultscontrasting

confidence: 57%

CO2 in Lyotropic Liquid Crystals: Phase Equilibria Behavior and Rheology

et al. 2019

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“…The use of thermotropic LCs for gas sorption was already investigated during the 1990s. In the past few years, there have been several publications related to the use of LCs [12,13,14] and polymeric liquid crystals (PLCs) [15] for gas sorption, although at that time they were not considered as solvents for CO 2 capture. In 2008, Gross and Jansens suggested a new process using liquid crystals as an alternative technology to capture CO 2 [7].…”

Section: Introductionmentioning

confidence: 99%

“…The principle behind the use of thermotropic LCs for CO 2 sorption is based on the phase transition from the liquid crystalline state to the isotropic liquid state or to the crystalline state. The technology takes advantage of the fast switch between the isotropic and liquid crystalline state triggered by temperature, as well as the difference in solubility of CO 2 between these two states [7,11,13,14]. In this work, we would like to investigate the potential use of lyotropic liquid crystals for CO 2 capture and storage.…”

Section: Introductionmentioning

confidence: 99%

CO2 in Lyotropic Liquid Crystals: Monoethanolamine-Facilitated Uptake and Swelling

et al. 2018

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Ternary systems consisting of amphiphilic block copolymers/water/monoethanolamine (MEA) have been studied as potential solvents for carbon capture and storage (CCS). The phase behavior of two poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) copolymers with average compositions (EO) 8 (PO) 47 (EO) 8 (L92) and (EO) 3 (PO) 50 (EO) 3 (L81) have been investigated by cross-polarized visual observation and small angle X-ray scattering (SAXS). The respective ternary phase diagrams have been studied for systems containing MEA and the equivalent systems containing CO 2 -loaded MEA. The presence of MEA loaded with CO 2 hinders self-association, preventing the formation of liquid crystalline phases. One-phase liquid crystalline regions were found at low MEA concentrations (below 20 wt %) in L92. In the case of L81, only one one-phase region consisting of coexisting lamellar and disordered aggregates was found at 5 wt % MEA. The swelling of the liquid crystalline phases with MEA was investigated along designated dilution lines. The lattice parameters of L92 liquid crystals decrease upon addition of MEA, whereas L81 aggregates show the opposite behavior.

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“…Past studies have reported that the solubilities of N 2 , CO 2 , and Ar in LCs increase weakly with temperature. 50 Assuming the temperature dependence of the solubility of toluene in our study to be similar to that of CO 2 in MBBA (N-(4-methoxybenzylidene)-4-butylaniline, a compound that forms a room-temperature nematic phase), 50 we estimate the solubility of toluene to increase by a factor of 1.8 with temperature from 25 to 40 °C. This leads us to predict that the response of the PSBP to 400 ppm toluene at 40 °C will be similar to 720 ppm of toluene at 25 °C, a prediction that is consistent with our experimental observations [−3.5 ± 0.3 for 720 ppm of toluene at 25 °C (Figure S3, Supporting Information) vs −3.8 ± 0.6 for 400 ppm toluene at 40 °C (Figure 6b)].…”

Section: ■ Resultsmentioning

confidence: 89%

Structural and Optical Response of Polymer-Stabilized Blue Phase Liquid Crystal Films to Volatile Organic Compounds

Yang

Kim

Wang

et al. 2020

ACS Appl. Mater. Interfaces

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Engineering useful mechanical properties into stimuli-responsive soft materials without compromising their responsiveness is, in many cases, an unresolved challenge. For example, polymer networks formed within blue-phase liquid crystals (BPs) have been shown to form mechanically robust films, but the impact of polymer networks on the response of these soft materials to chemical stimuli has not been explored. Here, we report on the response of polymer-stabilized BPs (PSBPs) to volatile organic compounds (VOCs, using toluene as a model compound) and compare the response to BPs without polymer stabilization and to polymerized nematic and cholesteric phases. We find that PSBPs generate an optical response to toluene vapor (change in reflection intensity under crossed polars) that is sixfold greater in sensitivity than the polymerized nematic or cholesteric phases and with a limit of detection (140 ± 10 ppm at 25 °C) that is relevant to the measurement of permissible exposure limits for humans. Additionally, when compared to BPs that have not been polymerized, PSBPs respond to a broader range of toluene vapor concentrations (5000 vs <1000 ppm) over a wider temperature interval (25–45 vs 45–53 °C). We place these experimental observations into the context of a simple thermodynamic model to explore how the PSBP response reflects the effect of toluene on competing contributions of double-twisted LC cylinders, disclinations, and polymer network to the free energy that controls the PSBP lattice spacing. Overall, we conclude that the mechanical and thermal stability of PSBPs, when combined with their optical responsiveness to toluene, make this class of self-supporting LCs a promising one as the basis of passive and compact (e.g., wearable) sensors for VOCs.

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Sorption and Diffusion of Gases in Liquid Crystalline Substances

Cited by 15 publications

References 15 publications

CO2 in Lyotropic Liquid Crystals: Phase Equilibria Behavior and Rheology

CO2 in Lyotropic Liquid Crystals: Phase Equilibria Behavior and Rheology

CO2 in Lyotropic Liquid Crystals: Monoethanolamine-Facilitated Uptake and Swelling

Structural and Optical Response of Polymer-Stabilized Blue Phase Liquid Crystal Films to Volatile Organic Compounds

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