Using an atomic force microscopy, we have measured the separation dependence of the force between an atomically flat mica sheet and a micrometer-sized glass sphere immersed in the nematic liquid crystal. As the mica surface induces a strong parallel alignment and the treated glass sphere induces a strong perpendicular alignment on the liquid crystal, a repulsive force is observed due to the elastically deformed nematic liquid crystal. We observe that below a critical separation d(th) approximate to 10 nm, the system undergoes a structural transition, thus relaxing the distortion. The results are interpreted within the eigenvalue exchange mechanism using the Landau-de Gennes tensorial approach.

Mechanically Induced Biaxial Transition in a Nanoconfined Nematic Liquid Crystal with a Topological Defect

BARBERI, Riccardo Cristoforo;
2009-01-01

Abstract

Using an atomic force microscopy, we have measured the separation dependence of the force between an atomically flat mica sheet and a micrometer-sized glass sphere immersed in the nematic liquid crystal. As the mica surface induces a strong parallel alignment and the treated glass sphere induces a strong perpendicular alignment on the liquid crystal, a repulsive force is observed due to the elastically deformed nematic liquid crystal. We observe that below a critical separation d(th) approximate to 10 nm, the system undergoes a structural transition, thus relaxing the distortion. The results are interpreted within the eigenvalue exchange mechanism using the Landau-de Gennes tensorial approach.
2009
nematic defect; atomic force microscope; nano-confinement; nano-forces
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/129960
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