Nematic phase of rodlike polymers. II. Polydomain predictions in the tumbling regime
作者:
G. Marrucci,
P. L. Maffettone,
期刊:
Journal of Rheology
(AIP Available online 1990)
卷期:
Volume 34,
issue 8
页码: 1231-1244
ISSN:0148-6055
年代: 1990
DOI:10.1122/1.550084
出版商: The Society of Rheology
关键词: Tumbling regime;Polydomain structure;Frank elasticity;Transient shear flow;Steady shear flow;POLYMERS;NEMATIC CRYSTALS;SHEAR;RHEOLOGY;TWO−DIMENSIONAL CALCULATIONS;TRANSIENTS
数据来源: AIP
摘要:
The two‐dimensional model previously considered is here used to obtain predictions in the complex situation of the tumbling regime which prevails at low shear rates. Although each domain is permanently in a time‐dependent, periodic regime, the macroscopic response can be stationary in time because of the well‐known polydomain structure. First, the average steady rheological response for this situation is calculated by taking a polydomain structure which neglects interdomain interactions. Although the steady state predictions thus obtained favorably compare with the experimental results throughout the range of shear rates, the transient start‐up responses do not, because of the crucial role played by the interactions in such a case. These interactions, due to Frank elasticity, are then introduced in the model in the simplest possible way, i.e., by use of a mean field potential. Under this assumption, also the predictions of transient behavior in the tumbling regime show the correct qualitative features.
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