Temperature Dependent Pitch in Cholesteric Phase

Kimura, Hiroyuki; Hosino, Masahito; Nakano, Huzio

doi:10.1051/jphyscol:1979335

Cited by 33 publications

(19 citation statements)

References 8 publications

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“…For example, the theory proposed by Kimura et al . [ 3 ] predicts a linear dependence of the reciprocal pitch against ϕ(1 – ϕ/3)/(1 – ϕ) 2 , where ϕ is the polymer concentration, which is in fairly good agreement with the experiments [ 4 ]. Due to cellulose relatively stiff cellulose backbone, which forces a parallel orientation of the chains, a wide range of cellulose derivatives was found to form both lyotropic and thermotropic chiral nematic liquid crystals [ 5 ].…”

Section: Introductionsupporting

confidence: 80%

From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials

2014

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Liquid crystalline cellulosic-based solutions described by distinctive properties are at the origin of different kinds of multifunctional materials with unique characteristics. These solutions can form chiral nematic phases at rest, with tuneable photonic behavior, and exhibit a complex behavior associated with the onset of a network of director field defects under shear. Techniques, such as Nuclear Magnetic Resonance (NMR), Rheology coupled with NMR (Rheo-NMR), rheology, optical methods, Magnetic Resonance Imaging (MRI), Wide Angle X-rays Scattering (WAXS), were extensively used to enlighten the liquid crystalline characteristics of these cellulosic solutions. Cellulosic films produced by shear casting and fibers by electrospinning, from these liquid crystalline solutions, have regained wider attention due to recognition of their innovative properties associated to their biocompatibility. Electrospun membranes composed by helical and spiral shape fibers allow the achievement of large surface areas, leading to the improvement of the performance of this kind of systems. The moisture response, light modulated, wettability and the capability of orienting protein and cellulose crystals, opened a wide range of new applications to the shear casted films. Characterization by NMR, X-rays, tensile tests, AFM, and optical methods allowed detailed characterization of those soft cellulosic materials. In this work, special attention will be given to recent developments, including, among others, a moisture driven cellulosic motor and electro-optical devices.

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Section: Introductionsupporting

confidence: 80%

From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials

2014

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“…The side chains assume the helical arrangement forced by the helical conformation of the main chain, produce a screw-like van der Waals surface on the exterior of main-chain backbone, and cause the twist by their steric interaction. Kimura et al considered the temperature dependence of cholesteric pitch by a coupling of these two effects and showed that the twisting power, q = 2π/P , is given by the following equation [26,27]:…”

Section: Discussionmentioning

confidence: 99%

Thermotropic Cholesteric Liquid Crystals in Ester Derivatives of Hydroxypropylcellulose

Kosho¹,

Hiramatsu²,

Nishi³

et al. 1999

High Performance Polymers

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“…51 This entropic contribution affects the temperature dependence of a cholesteric pitch. 43 The theory can be extended to nematic and cholesteric liquid crystal mixtures, binary mixtures of cholesteric liquid crystals, cholesteric liquid crystalline polymers, and lyotropic cholesteric phases.…”

Section: Discussionmentioning

confidence: 99%

“…[30][31][32][33] To describe cholesteric phases, the chiral dispersion intermolecular interactions have been treated by many authors. [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] The configuration of the constituent ith molecule is characterized by its position vector r i and its orientation vector i . It has been shown that the intermolecular chiral interaction is given by the term ( 1 × 2 •r 12 )P 1 ( 1 • 2 ) in the lowest order, wherer 12 = (r 1 − r 2 )/|r 1 − r 2 |.…”

Section: Introductionmentioning

confidence: 99%

Theory of polymer-dispersed cholesteric liquid crystals

Matsuyama

2013

The Journal of Chemical Physics

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A mean field theory is presented to describe cholesteric phases in mixtures of a polymer and a cholesteric liquid crystal. Taking into account an anisotropic coupling between a polymer and a liquid crystal, we examine the helical pitch, twist elastic constant, and phase separations. Analytical expressions of the helical pitch of a cholesteric phase and the twist elastic constant are derived as a function of the orientational order parameters of a polymer and a liquid crystal and two intermolecular interaction parameters. We also find isotropic-cholesteric, cholesteric-cholesteric phase separations, and polymer-induced cholesteric phase on the temperature-concentration plane. We demonstrate that an anisotropic coupling between a polymer and a liquid crystal can stabilize a cholesteric phase in the mixtures. Our theory can also apply to mixtures of a nematic liquid crystal and a chiral dopant. We discuss the helical twisting power, which depends on temperature, concentration, and orientational order parameters. It is shown that our theory can qualitatively explain experimental observations.

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Temperature Dependent Pitch in Cholesteric Phase

Cited by 33 publications

References 8 publications

From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials

From Cellulosic Based Liquid Crystalline Sheared Solutions to 1D and 2D Soft Materials

Thermotropic Cholesteric Liquid Crystals in Ester Derivatives of Hydroxypropylcellulose

Theory of polymer-dispersed cholesteric liquid crystals

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