Abstract
The resistance to shear flow is investigated theoretically for polar liquid crystals, such as 4- n -octyl- 4'- and 4- n -octyloxy-4'-cyanobiphenyls. It is established that the lowest resistance to shear flow at temperatures in the vicinity of the nematic-smectic A phase transition point T NA is observed when the nematic director is ori- ented perpendicular to both the flow velocity vector and the flow velocity gradient. The three Miesowicz shear viscosity coefficients η i ( i = 1-3) at temperatures close to the phase transition temperature (tens of millikelvins from T NA ) and far from this transition are calculated in the framework of the Ericksen-Leslie theory. The decrease in the viscosity coefficients in the order η 2 > η 1 > η 3 is explained by the fact that fluctuations of the local smectic order in the nematic phase lead to a singular behavior of the viscosity coefficient η 2 , whereas the other two viscosity coefficients η 1 and η 3 are not affected by order parameter fluctuations. © 2004 MAIK "Nauka/Interperiodica".
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
