Deformation and Structural Re-formation of Lyotropic Cholesteric Liquid Crystal of Hydroxypropyl Cellulose + Water System

Asada, Tadahiro; Toda, Kentaro; Onogi, Shigeharu

doi:10.1080/00268948108073566

Cited by 53 publications

(40 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The shear-induced cholesteric to nematic transition in films prepared from lyotropic cellulosic mesophases has also been investigated. [6] Electrostatic fiber spinning or ''electrospinning'' is a process for drawing fibers with sub-micrometer diameters through the action of electrostatic forces. [7,8] The nonwoven mats thus produced are finding applications in filtration, protective clothing and biomedicine.…”

mentioning

confidence: 99%

Helical Twisting of Electrospun Liquid Crystalline Cellulose Micro‐ and Nanofibers

et al. 2008

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 99%

Helical Twisting of Electrospun Liquid Crystalline Cellulose Micro‐ and Nanofibers

et al. 2008

View full text Add to dashboard Cite

show abstract

“…When subject to shear, thermotropic cholesteric cellulose esters can present complex viscoelastic behaviour, showing rich anisotropic mechanical properties, as described by Onogi and Asada [4] for liquid crystalline polymers (LCP). These systems may undergo a cholesteric-nematic transition under shear [5] and present generally remarkable optical characteristics [6].…”

Section: A N U S C R I P Tmentioning

confidence: 99%

Rheo-optical characterization of liquid crystalline acetoxypropylcellulose melt undergoing large shear flow and relaxation after flow cessation

Teixeira

Fernandes

Canejo

et al. 2015

Polymer

View full text Add to dashboard Cite

The rheological and structural characteristics of acetoxypropylcellulose (APC) nematic melt are studied at shear rates ranging from 10 s -1 to 1000 s -1 which are relevant to extrusion based processes. APC shows a monotonic shear thinning behavior over the range of shear rates tested. The negative extrudate-swell shows a minimum when a critical shear rate ߛሶ is reached. For shear rates smaller than ߛሶ , the flow-induced texture consists in two set of bands aligned parallel and normal to the flow direction. At shear rates larger than ߛሶ , the flow induced texture is reminiscent from a 2 fluids structure. Close to the shearing walls, domains elongated along the flow direction and stacked along the vorticity are imaged with POM, whereas SALS patterns indicate that the bulk of the sheared APC is made of elliptical domains oriented along the vorticity. No full nematic alignment is achieved at the largest shear rate tested. Below ߛሶ , the stress relaxation is described by a stretched exponential. Above ߛሶ , the stress relaxation is described by a fast and a slow process. The latter coincides with the growth of normal bands thicknesses, as the APC texture after flow cessation consists in two types of bands with parallel and normal orientations relative to the flow direction. Both bands thicknesses do not depend on the applied shear rate, in contrast to their orientation.

show abstract

“…15 Asada et a1. 16 have followed the reforming of the cholesteric structure of aqueous (hydroxypropy1)cellulose mesophases by rheo-optical measurements of the reflection band. The results for their controlled shear conditions were explained by a reorientation and distribution of the cholesteric axes.…”

Section: Oooo6mentioning

confidence: 99%

Birefringence of a polymeric cholesteric liquid crystal measured by refractometry

Laivins

Gray

1987

J of Applied Polymer Sci

View full text Add to dashboard Cite

SynopsisThe Abbe refractometer provides a convenient way to measure the refractive indices and birefringence of polymeric liquid crystalline solutions. The cholesteric mesophase formed by (acetoxypropyl) cellulose and its solutions in dibutyl phthalate were examined at 26°C and 5OOC. The measured refractive indices were dependent on the direction of shear when the polymer was applied to the refractometer plates. The initial shear-induced nematic-like order relaxed slowly to the equilibrium planar cholesteric structure. The refractive index for the isotropic solutions and the two refractive indices for the anisotropic solutions all varied linearly with polymer concentration, and the width of the intermediate two-phase region was readily determined. The changes in refractive index with polymer concentration and with orientation on the refractometer plate were rationalized with E simple model of the cellulosic mesophase, and an order parameter of 0.7 was estimated. The layer birefringence calculated from optical rotatory dispersion measurements of the cholesteric reflection band intensity was in good agreement with the birefringence measurements.

show abstract

Deformation and Structural Re-formation of Lyotropic Cholesteric Liquid Crystal of Hydroxypropyl Cellulose + Water System

Cited by 53 publications

References 6 publications

Helical Twisting of Electrospun Liquid Crystalline Cellulose Micro‐ and Nanofibers

Helical Twisting of Electrospun Liquid Crystalline Cellulose Micro‐ and Nanofibers

Rheo-optical characterization of liquid crystalline acetoxypropylcellulose melt undergoing large shear flow and relaxation after flow cessation

Birefringence of a polymeric cholesteric liquid crystal measured by refractometry

Contact Info

Product

Resources

About