scholarly journals Direct measurements of structural forces and twist transitions in cholesteric liquid crystal films with a surface force apparatus

Soft Matter ◽  
2019 ◽  
Vol 15 (24) ◽  
pp. 4905-4914
Author(s):  
Weichao Zheng ◽  
Carla Sofia Perez-Martinez ◽  
Gia Petriashvili ◽  
Susan Perkin ◽  
Bruno Zappone
Keyword(s):  
Liquid Crystal ◽  
Cholesteric Liquid Crystal ◽  
Surface Force ◽  
Surface Force Apparatus ◽  
Liquid Crystal Films ◽  
Structural Forces ◽  
Direct Measurements ◽  
Crystal Films

Mechanical micro-confinement of a cholesteric liquid crystal between crossed cylinders produces dislocations, twist transitions and oscillatory structural forces.

Optically switchable biphotonic gratings based on dye-doped cholesteric liquid crystal films

2007 ◽  
Vol 90 (26) ◽  
pp. 261103 ◽  
Author(s):  
H.-C. Yeh ◽  
G.-H. Chen ◽  
C.-R. Lee ◽  
T.-S. Mo
Keyword(s):  
Liquid Crystal ◽  
Cholesteric Liquid Crystal ◽  
Liquid Crystal Films ◽  
Crystal Films

scholarly journals Structural-induced lubricity of liquid crystal nanomaterials of cholesterol at metal friction

2019 ◽  
Vol 488 (1) ◽  
pp. 24-28
Author(s):  
V. I. Kolesnikov ◽  
S. F. Ermakov ◽  
E. B. Shershnev ◽  
A. P. Sychev
Keyword(s):  
Liquid Crystal ◽  
Cholesteric Liquid Crystal ◽  
Friction Zone ◽  
Temperature Changes ◽  
Temperature Range ◽  
Liquid Crystal Films ◽  
Crystal Films ◽  
Lubricating Capacity ◽  
Ordered State ◽  
Metal Friction

Experimentally, it was found that with the change in temperature there is a structural-induced increase in the lubricating capacity of liquid-crystal nanomaterials induced by transformations in the cholesteric mesophase. It is shown that in this temperature range, the minimum values of the friction coefficient practically coincide with the peak values of the dynamic viscosity, which together indicates in favor of the ordered state of the cholesterol liquid-crystal structures at these temperatures. As a result, it can be assumed that in this temperature range, spirally twisted layers of liquid-crystal cholesterol molecules with high antifriction action are formed in the friction zone. It is noted that the thickness of the friction-implemented cholesteric liquid-crystal films is sensitive to temperature changes in the contact area, changing the color and energy loss.

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