Viscosity of a liquid crystalline polymer solution with a polydomain or a band texture

1997 ◽  
Vol 36 (6) ◽  
pp. 628-631
Author(s):  
Vassilios T. Tsakalos ◽  
Edith Peuvrel-Disdier ◽  
P. Navard
Keyword(s):  
Polymer Solution ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer

Flow Induced Unstable Structure of Liquid Crystalline Polymer Solution in L-Shaped Slit Channels

2008 ◽  
Vol 130 (8) ◽  
Author(s):  
Takatsune Narumi ◽  
Jun Fukada ◽  
Satoru Kiryu ◽  
Shinji Toga ◽  
Tomiichi Hasegawa
Keyword(s):  
Polymer Solution ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Flow Behavior ◽  
Crystalline Polymer ◽  
Test Fluid ◽  
Radius Of Curvature ◽  
Unstable Behavior ◽  
Corner Flow ◽  
Side Flow

An experimental study has been conducted on unstable structures induced in two-dimensional slit flows of liquid crystalline polymer solution. 50wt% aqueous solution of hydroxyl-propylcellulose (HPC) was utilized as a test fluid and its flow behavior in L-shaped slit channels with a cross section of 1mm height and 16mm width was measured optically. The inner corner of the L-shaped channel was rounded off in order to clarify the influence of the radius of curvature on the unstable behavior. A conversing curved channel was also tested. The flow patterns of the HPC solution in the channels were visualized with two crossed polarizers and we observed that typical wavy textures generated in the upstream of the corner almost disappeared after the corner flow. However, an unstable texture was developed again only from the inner corner in downstream flow. The fluctuation of the orientation angle and dichroism were also measured with a laser opto-rheometric system and it was found that the unstable behaviors of the HPC solution have periodic oscillatory characteristics at a typical frequency. In the inner side flow after the corner, the periodic motion became larger toward the downstream and then higher harmonic oscillations were superimposed. Larger rounding off of the inner corner suppressed the redevelopment of unstable behavior, and it is considered that the rapid regrowth of unstable behavior was caused by rapid deceleration at the corner flow. Moreover, the unstable structure was stabilized with an accelerated (elongated) region in the corner flow and the converging channel was helpful to obtain a stable structure in the downstream region.

Mechanism of the Occurrence of Wavy Texture in Slit Flows of a Liquid Crystalline Polymer Solution

2002 ◽  
Vol 2002.77 (0) ◽  
pp. _13-49_-_13-50_
Author(s):  
Masatada SHINDOU ◽  
Noriyasu MORI ◽  
Tsutomu TAKAHASHI ◽  
Kiyoji NAKAMURA
Keyword(s):  
Polymer Solution ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Wavy Texture

Effect of Electric Fields on the Rheological Properties of the Isotropic Phase of phic/p-Xylene Solutions

2005 ◽  
Vol 15 (3) ◽  
pp. 172-176 ◽  
Author(s):  
Todd J. Menna ◽  
Frank E. Filisko ◽  
Rachel A. Lynch
Keyword(s):  
Field Strength ◽  
Polymer Solution ◽  
Rheological Properties ◽  
Electric Fields ◽  
Liquid Crystalline Polymer ◽  
Liquid Crystalline ◽  
Crystalline Polymer ◽  
Isotropic Phase ◽  
Ac Electric Fields

Abstract The effect of high ac electric fields upon a liquid crystalline polymer solution, poly(n-hexyl isocyanate) in p-xylene, is examined. The results show that the solutions exhibit an increase in rheological properties proportional to the strength of the field at concentrations well below those exhibiting liquid crystalline behavior. The effects of frequency and field strength are examined as a means to explain this previously unreported phenomenon.

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