Liquid Crystalline Phase and Gel−Sol Transitions for Concentrated Microcrystalline Cellulose (MCC)/1-Ethyl-3-methylimidazolium Acetate (EMIMAc) Solutions

Song, Hongzan; Niu, Yanhua; Wang, Zhigang; Zhang, Jun

doi:10.1021/bm101426p

Cited by 96 publications

(84 citation statements)

References 60 publications

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“…Liquid crystalline structures have also been observed in cellulose-IL solutions. Kosan [61,62]. They detected the concentration threshold upon which lyotropic phases became visible by means of polarized light microscopy and oscillatory shearrheological measurements.…”

Section: Rheology Of Cellulose-il Solutionsmentioning

confidence: 99%

Ionic Liquids for the Production of Man-Made Cellulosic Fibers: Opportunities and Challenges

Hummel

Michud

Tanttu

et al. 2015

Advances in Polymer Science

132

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The constant worldwide increase in consumption of goods will also affect the textile market. The demand for cellulosic textile fibers is predicted to increase at such a rate that by 2030 there will be a considerable shortage, estimated at~15 million tons annually. Currently, man-made cellulosic fibers are produced commercially via the viscose and Lyocell™ processes. Ionic liquids (ILs) have been proposed as alternative solvents to circumvent certain problems associated with these existing processes. We first provide a comprehensive review of the progress in fiber spinning based on ILs over the last decade. A summary of the reports on the preparation of pure cellulosic and composite fibers is complemented by an overview of the rheological characteristics and thermal degradation of cellulose-IL solutions. In the second part, we present a non-imidazolium-based ionic liquid, 1,5-diazabicyclo[4.3.0]non-5-enium acetate, as an excellent solvent for cellulose fiber spinning. The use of moderate process temperatures in this process avoids the otherwise extensive cellulose degradation. The structural and morphological properties of the spun fibers are described, as determined by WAXS, birefringence, and SEM measurements. Mechanical properties are also reported. Further, the suitability of the spun fibers to produce yarns for various textile applications is discussed.

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Section: Rheology Of Cellulose-il Solutionsmentioning

confidence: 99%

Ionic Liquids for the Production of Man-Made Cellulosic Fibers: Opportunities and Challenges

Hummel

Michud

Tanttu

et al. 2015

Advances in Polymer Science

132

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“…The small frequency dependence at long time scales (low frequencies) in the PEDOT gels compared to the NP-10 and EDOT gels is consistent with the finite relaxation time (τ) usually found in surfactant gels in contrast with the near infinite relaxation time of cross-linked gels. 61–62 …”

Section: Resultsmentioning

confidence: 99%

Synthesis and characterization of bicontinuous cubic poly(3,4-ethylene dioxythiophene) gyroid (PEDOT GYR) gels

Cho

Shim

et al. 2015

Phys. Chem. Chem. Phys.

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We describe the synthesis and characterization of bicontinuous cubic poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymer gels prepared within lyotropic cubic poly(oxyethylene)10 nonylphenol ether (NP-10) templates with Ia3̄d (gyroid, GYR) symmetry. The chemical polymerization of EDOT monomer in the hydrophobic channels of the NP-10 GYR phase was initiated by AgNO3, a mild oxidant that is activated when exposed to ultraviolet (UV) radiation. The morphology and physical properties of the resulting PEDOT gels were examined as a function of temperature and frequency using optical and electron microscopy, small angle X-ray scattering (SAXS), dynamic mechanical spectroscopy, and electrochemical impedance spectroscopy (EIS). Microscopy and SAXS results showed that the PEDOT gels remained ordered and stable after the UV-initiated chemical polymerization, confirming the successful templated-synthesis of PEDOT in bicontinuous GYR nanostructures. In comparison to unpolymerized 3,4-ethylenedioxythiophene (EDOT) gel phases, the PEDOT structures had a higher storage modulus, presumably due to the formation of semi-rigid PEDOT-rich nanochannels. Additionally, the G′ for PEDOT gels decreased only modestly with increasing temperature, from ~1.2 × 103 Pa (10 °C) to ~7 × 104 Pa (40 °C), whereas G′ for the NP-10 and EDOT gels decreased dramatically, from ~5.0 × 104 Pa (10 °C) to ~1.5 × 102 Pa (40 °C). EIS revealed that the impedance of the PEDOT gels was smaller than the impedance of EDOT gels at both high frequencies (PEDOT ~102 Ω and EDOT 2 – 3 × 103 Ω at 105 Hz) and low frequencies (PEDOT 103–105 Ω and EDOT ~5 × 105 Ω at 10−1 Hz). These results indicated that PEDOT gels were highly ordered, mechanically stable and electrically conductive, and thus should be of interest for applications for which such properties are important, including low impedance and compliant coatings for biomedical electrodes.

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“…In 2002, Swatloski et al [23] reported that several ionic liquids (ILs) can act as direct solvents for chemically unmodified cellulose and, especially, that the use of 1-butyl-3-methylimidazolium chloride led to a viscous cellulose solution displaying optical birefringence at polymer concentrations of more than 10 wt%; however, detailed characterization of the anisotropic phase has not been made available. In 2011, it was reported that cellulose forms a molecular liquid crystalline phase in 1-ethy-3-methyimidazolium acetate solutions of >10 wt% concentration, whereas a critical gelation point was detected at a concentration slightly higher (by~2 wt%) than the anisotropic phase transition point [24].…”

Section: Fundamental Aspectsmentioning

confidence: 99%

Liquid Crystals of Cellulosics: Fascinating Ordered Structures for the Design of Functional Material Systems

Nishio

Sato

Sugimura

2015

Advances in Polymer Science

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This article surveys progress in both fundamental and applied research related to cellulosic liquid crystals, mainly of chiral nematic order. These liquid crystals are divided into two different classes, namely cellulosic macromolecules and cellulose nanocrystals (CNCs), depending on the mesogenic constituent. We start with a review of the fundamental and chiroptical characteristics of molecular liquid crystals of representative cellulose derivatives and then discuss recent efforts on the design and construction of functional material systems (such as stimulisensitive optical media and novel hybrids with minerals). These systems make use of the liquid crystalline molecular assembly of cellulosics. The survey of the other class of cellulosic liquid crystals deals with colloidal suspensions of CNCs obtained by acid hydrolysis of native cellulose fibers. Following the review of fundamental aspects related to the isotropic-anisotropic phase separation behavior of CNC suspensions, attention is directed to current applications of free-standing colored films, polymer composites reinforced with CNCs as mesofiller, and inorganic hybridizations using CNC chiral nematics as template. Some comments and the outlook for future explorations are also offered.

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Liquid Crystalline Phase and Gel−Sol Transitions for Concentrated Microcrystalline Cellulose (MCC)/1-Ethyl-3-methylimidazolium Acetate (EMIMAc) Solutions

Cited by 96 publications

References 60 publications

Ionic Liquids for the Production of Man-Made Cellulosic Fibers: Opportunities and Challenges

Ionic Liquids for the Production of Man-Made Cellulosic Fibers: Opportunities and Challenges

Synthesis and characterization of bicontinuous cubic poly(3,4-ethylene dioxythiophene) gyroid (PEDOT GYR) gels

Liquid Crystals of Cellulosics: Fascinating Ordered Structures for the Design of Functional Material Systems

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