Magnetic-field-induced Fréedericksz transition and the dynamic response of nematic liquid-crystal films with a free surface

1991 ◽  
Vol 43 (6) ◽  
pp. 2848-2857 ◽  
Author(s):  
Shyu-Mou Chen ◽  
Ting-Chiang Hsieh ◽  
Ru-Pin Pan
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Liquid Crystal ◽  
Dynamic Response ◽  
Nematic Liquid Crystal ◽  
Freedericksz Transition ◽  
Liquid Crystal Films ◽  
Crystal Films ◽  
Fréedericksz Transition

scholarly journals Bifurcation analysis of the twist-Fréedericksz transition in a nematic liquid-crystal cell with pre-twist boundary conditions

2009 ◽  
Vol 20 (3) ◽  
pp. 269-287 ◽  
Author(s):  
FERNANDO P. DA COSTA ◽  
EUGENE C. GARTLAND ◽  
MICHAEL GRINFELD ◽  
JOÃO T. PINTO
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Boundary Conditions ◽  
Nematic Liquid Crystal ◽  
Pitchfork Bifurcation ◽  
Critical Magnetic Field ◽  
Twist Boundary ◽  
Freedericksz Transition ◽  
Diamagnetic Anisotropy ◽  
Fréedericksz Transition

Motivated by a recent investigation of Millar and McKay [Director orientation of a twisted nematic under the influence of an in-plane magnetic field. Mol. Cryst. Liq. Cryst435, 277/[937]–286/[946] (2005)], we study the magnetic field twist-Fréedericksz transition for a nematic liquid crystal of positive diamagnetic anisotropy with strong anchoring and pre-twist boundary conditions. Despite the pre-twist, the system still possesses ℤ2 symmetry and a symmetry-breaking pitchfork bifurcation, which occurs at a critical magnetic-field strength that, as we prove, is above the threshold for the classical twist-Fréedericksz transition (which has no pre-twist). It was observed numerically by Millar and McKay that this instability occurs precisely at the point at which the ground-state solution loses its monotonicity (with respect to the position coordinate across the cell gap). We explain this surprising observation using a rigorous phase-space analysis.

scholarly journals Effects of spatially-varying substrate anchoring on instabilities and dewetting of thin nematic liquid crystal films

Soft Matter ◽  
2020 ◽  
Vol 16 (44) ◽  
pp. 10187-10197
Author(s):  
Michael-Angelo Y.-H. Lam ◽  
Lou Kondic ◽  
Linda J. Cummings
Keyword(s):  
Free Surface ◽  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Surface Evolution ◽  
Liquid Crystal Films ◽  
Crystal Films ◽  
Spatially Varying ◽  
Variable Substrate

We investigate (theoretically and numerically) free surface evolution of nematic liquid crystal films in the presence of variable substrate anchoring.

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