The texture in shear flow is discussed for nematic solutions of rodlike poly(1,4-phenylene terephthalamide), reported here, and poly(1,4-phenylene-2,6-benzobisthiazole), reported elsewhere. These are similar, with a sequence of scattering and visual features that develop with time, terminating at a level characteristic of the shear rate in steady state. With increasing shear rate in torsion between parallel disks, steady-state flow reveals sequentially a diffuse scattering with a turbid appearance, diffuse scattering with an opalescent appearance, a broad elliptical scattering along the radial direction with poorly-defined striations, a sharp scattering along the radial direction with well-defined striations along the flow, and a clear, highly birefringent sample, with little scattering. These same features are seen, in the same sequence in time, in transient behavior leading to steady state. This behavior is attributed to the development of striations with twist distortions alternating in angle relative to the flow, and essentially in the sample plane in the fast steady-state flow, reflecting the lower free energy of that distortion in comparison with bend and splay distortions, especially near the parallel plates of the rheometer. The deterioration of this texture at slower flows is associated with increasing distortions out of the sample plane, leading to an essentially chaotic spatial distribution of the order tensor at a slow flow.
Skip Nav Destination
,
Article navigation
January 2003
Research Article|
January 01 2003
Studies on the texture of nematic solutions of rodlike polymers. 3. Rheo-optical and rheological behavior in shear
Zhanjie Tan;
Zhanjie Tan
Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
Search for other works by this author on:
Guy C. Berry
Guy C. Berry
Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
Search for other works by this author on:
Zhanjie Tan
Guy C. Berry
Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213
J. Rheol. 47, 73–104 (2003)
Article history
Received:
July 08 2002
Citation
Zhanjie Tan, Guy C. Berry; Studies on the texture of nematic solutions of rodlike polymers. 3. Rheo-optical and rheological behavior in shear. J. Rheol. 1 January 2003; 47 (1): 73–104. https://doi.org/10.1122/1.1530621
Download citation file:
Pay-Per-View Access
$40.00
Sign In
You could not be signed in. Please check your credentials and make sure you have an active account and try again.
Citing articles via
Rheo-SINDy: Finding a constitutive model from rheological data for complex fluids using sparse identification for nonlinear dynamics
Takeshi Sato, Souta Miyamoto, et al.
No yield stress required: Stress-activated flow in simple yield-stress fluids
G. Pagani, M. Hofmann, et al.
Linear viscoelasticity of nanocolloidal suspensions from probe rheology molecular simulations
Dinesh Sundaravadivelu Devarajan, Rajesh Khare
Related Content
Rheo‐optical studies on aligned nematic solutions of a rodlike polymer
J. Rheol. (April 1991)
Bingham Award Lecture−1990: Rheological and rheo‐optical studies on nematic solutions of a rodlike polymer
J. Rheol. (August 1991)
Rheological properties of rodlike polymers in solution. IV. Rheology of blends of nylon and a rodlike chain
J. Rheol. (October 1990)
A rheo-optical apparatus for simultaneous detection of rheology, small-angle light scattering, and optical microscopy under transient, oscillatory, and continuous shear flows
Rev. Sci. Instrum. (May 1999)
A novel rheo-optical device for studying complex fluids in a double shear plate geometry
Rev. Sci. Instrum. (January 2013)