Study of flow in a smectic liquid crystal in the X-ray Surface Forces Apparatus

Autor: Idziak, S. H. J., Koltover, I., Liang, K. S., Israelachvili, J. N., Safinya, C. R.
Zdroj: International Journal of Thermophysics; March 1995, Vol. 16 Issue: 2 p299-307, 9p
Abstrakt: We describe the newly invented X-Ray Surface Forces Apparatus (X-SFA) which allows the simultaneous measurement of forces and collective structures of confined complex fluids under static and flow conditions. The structure of the smectic liquid crystal 8CB (4-cyano-4'-octylbiphenyl) f confined between two mica surfaces with separation ranging from 4000 to 20,000 A was measured. At small gaps and no shear, the smectic layers take on distinct stable orientations, including the bulk forbidden “h” orientation. which persist under low shear ( $$\dot \gamma $$ ? 30 s-1). However, at higher shear rates $$\dot \gamma $$ ? 360 s-1) the shear acts to dramatically order and align the smectic layers into a single“a” orientation.
Databáze: Supplemental Index
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