Gas transport properties of liquid crystalline polysiloxane with laterally attached side chain

Kawakami, Hiroyoshi; Mori, Yasumasa; Abe, Hirokazu; Nagaoka, Shoji

doi:10.1016/s0376-7388(97)00086-0

Cited by 15 publications

(9 citation statements)

References 21 publications

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“…The applications of SCLCPs have been reviewed in several aspects and have been found to focus on the following several fields: optical data storage, nonlinear optics, chromatographic stationary phases, separation membranes, 211 and other areas. 7,8 In fact, similar to conventional end-on SCLCPs, many efforts have been devoted to developing the applications of side-on SCLCPs in almost the same fields mentioned above.…”

Section: Properties and Applicationsmentioning

confidence: 99%

Mesogen-jacketed liquid crystalline polymers

et al. 2010

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This critical review covers the recent progress in the research of mesogen-jacketed liquid crystalline polymers (MJLCPs), special side-on side-chain liquid crystalline polymers with very short spacers or without spacers. MJLCPs can self-organize into supramolecular columnar phases with the polymer chains aligned parallel to one another or smectic phases with the backbones embedded in the smectic layers. The semi-rigid rod-like MJLCP with a tunable rod shape in both length and diameter provides an excellent building block in designing novel rod-coil liquid crystalline block copolymers which can self-assemble into hierarchical supramolecular nanostructures depending on the competition between liquid crystal formation and microphase separation (229 references).

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Section: Properties and Applicationsmentioning

confidence: 99%

Mesogen-jacketed liquid crystalline polymers

et al. 2010

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“…Investigations of the selective pervaporation of volatile organic compounds and the enantioselective properties of cholesteric liquid crystalline membranes have been reported [13,14,15,16]. In addition, there have been several studies of side-chain LCPs focusing on the relationship between polymer microstructure and transport properties [17,18,19,20,21,22]. For example, Kawakami et al [21] have shown that the overall permeability of a LC polysiloxane with side-chain mesogenic groups was governed by an activated diffusion mechanism, as has been observed in other glassy polymers.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, there have been several studies of side-chain LCPs focusing on the relationship between polymer microstructure and transport properties [17,18,19,20,21,22]. For example, Kawakami et al [21] have shown that the overall permeability of a LC polysiloxane with side-chain mesogenic groups was governed by an activated diffusion mechanism, as has been observed in other glassy polymers. In this particular case, the transport properties were dominated by the polysiloxane main chain, which has higher flexibility and free volume.…”

Section: Introductionmentioning

confidence: 99%

Temperature-Dependent Gas Transport Behavior in Cross-Linked Liquid Crystalline Polyacrylate Membranes

et al. 2019

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Stable, cross-linked, liquid crystalline polymer (LCP) films for membrane separation applications have been fabricated from the mesogenic monomer 11-(4-cyanobiphenyl-4′-yloxy) undecyl methacrylate (CNBPh), non-mesogenic monomer 2-ethylhexyl acrylate (2-EHA), and cross-linker ethylene glycol dimethacrylate (EGDMA) using an in-situ free radical polymerization technique with UV initiation. The phase behavior of the LCP membranes was characterized using differential scanning calorimetry (DSC) and X-ray scattering, and indicated the formation of a nematic liquid crystalline (LC) phase above the glass transition temperature. The single gas transport behavior of CO2, CH4, propane, and propylene in the cross-linked LCP membranes was investigated for a range of temperatures in the LC mesophase and the isotropic phase. Solubility of the gases was dependent not only on the condensability in the LC mesophase, but also on favorable molecular interactions of penetrant gas molecules exhibiting a charge separation, such as CO2 and propylene, with the ordered polar mesogenic side chains of the LCP. Selectivities for various gas pairs generally decreased with increasing temperature and were discontinuous across the nematic–sotropic transition. Sorption behavior of CO2 and propylene exhibited a significant change due to a decrease in favorable intermolecular interactions in the disordered isotropic phase. Higher cross-link densities in the membrane generally led to decreased selectivity at low temperatures when the main chain motion was limited by the lack of mesogen mobility in the ordered nematic phase. However, at higher temperatures, increasing the cross-link density increased selectivity as the cross-links acted to limit chain mobility. Mixed gas permeation measurements for propylene and propane showed close agreement with the results of the single gas permeation experiments.

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“…Percec and his colleagues synthesized a series of side-chain end-on (mesogens are terminally attached) liquid crystalline polysiloxanes bearing macroheterocyclic ligands, half-disk moieties, heterocycloalkanediyl groups, , and methylstilbene groups. , Hardouin et al studied series of side-chain side-on (mesogens are laterally attached) liquid crystalline polysiloxanes or copolysiloxanes, and found that the spacer length, the aliphatic tail length, and the content of mesogenic groups (“dilution” effect) markedly influenced the mesomorphic and thermodynamic properties of these polymers. − Besides side-chain LCPs, main-chain liquid crystalline polymers (MCLCPs) with mesogenic units and siloxane spacers in the main chain were also reported. − Recently, Zhou et al prepared several mesogen-jacketed liquid crystalline polymers (MJLCPs) with polysiloxane backbones and discovered that the mesogen-jacketed effect could force polysiloxanes to self-assemble into supramolecular columnar nematic or smectic liquid crystalline phases . Furthermore, functionalized liquid crystalline polysiloxanes have been applied as light emitting, ferroelectric, − gas transportation, and chromatography materials.…”

Section: Introductionmentioning

confidence: 99%

“…27−29 Recently, Zhou et al prepared several mesogen-jacketed liquid crystalline polymers (MJLCPs) with polysiloxane backbones and discovered that the mesogen-jacketed effect could force polysiloxanes to self-assemble into supramolecular columnar nematic or smectic liquid crystalline phases. 30 Furthermore, functionalized liquid crystalline polysiloxanes have been applied as light emitting, 31 ferroelectric, 32−34 gas transportation, 35 and chromatography 36 materials. Most of the above-reported polysiloxane-based LCPs and LCEs were prepared by hydrosilylation of polymethylhydrosiloxanes with mesogenic alkenes using Pt complex catalysts (Figure 1).…”

Section: ■ Introductionmentioning

confidence: 99%

Polysiloxane-Based Liquid Crystalline Polymers and Elastomers Prepared by Thiol–Ene Chemistry

et al. 2013

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A series of side-chain liquid crystalline polymers (LCPs) with polysiloxane backbones have been synthesized by grafting mesogenic monomers to poly[3-mercaptopropylmethylsiloxane] (PMMS) via thiol–ene click chemistry. Their properties were studied in detail by a combination of 1H NMR, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, polarized optical microscopy and small-angle X-ray scattering. In comparison with the traditional hydrosilylation method which requires noble metal catalyst platinum, this newly designed thiol–ene protocol produces polysiloxane-based LCPs with only anti-Markovnikov addition products under benign conditions. Moreover, by controlling the molar ratio of PMMS and mesogenic monomers, PMMS-based LCPs can be partially functionalized, meanwhile leaving spare mercapto groups, which could be further used as cross-linking sites to prepare polysiloxane-based liquid crystalline elastomers (LCEs). Besides preparing LCE fibers with a maximum contraction of 42% at nematic-to-isotropic transition temperature, we further explored the feasibility of using surface-rubbed cells to synthesize LCE films, but it turned out that this method could uniaxially align the mesogens of preformed short polymers but not the backbone chains so that the thermal-actuation effects of these films were modest.

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Gas transport properties of liquid crystalline polysiloxane with laterally attached side chain

Cited by 15 publications

References 21 publications

Mesogen-jacketed liquid crystalline polymers

Mesogen-jacketed liquid crystalline polymers

Temperature-Dependent Gas Transport Behavior in Cross-Linked Liquid Crystalline Polyacrylate Membranes

Polysiloxane-Based Liquid Crystalline Polymers and Elastomers Prepared by Thiol–Ene Chemistry

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