The response of a cholesteric liquid crystal film to mechanical confinement is theoretically investigated considering planar anchoring conditions on the limiting surfaces and pure twist distortion of the liquid crystal director. We evaluate the total twist angle and normal force acting on the surfaces as a function of the film thickness. Assuming the Rapini-Papoular functional form for the surface anchoring energy, we show that the surface twist angle undergoes discontinuous jumps or continuous transitions as a function of the film thickness and anchoring strength. The transitions take place at well-defined film thicknesses, related to the intrinsic periodicity of the cholesteric liquid crystal, and produce oscillations in the normal force and position of the optical band-gap as the film thickness is varied.
Twist transitions and force generation in cholesteric liquid crystal films / Barbero, Giovanni; Zheng, Weichao; Zappone, Bruno. - In: JOURNAL OF MOLECULAR LIQUIDS. - ISSN 0167-7322. - 267(2018), pp. 242-248.
|Titolo:||Twist transitions and force generation in cholesteric liquid crystal films|
|Data di pubblicazione:||2018|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1016/j.molliq.2017.11.014|
|Appare nelle tipologie:||1.1 Articolo in rivista|