Due to its low symmetry C2v, the dowser texture is characterised by a 2D unitary vector field or alternatively by a unitary complex field. For the same symmetry reasons, the dowser texture is sensitive, in first order, to perturbations such as thickness gradients, electric fields or flows. We will focus on corresponding properties called respectively: cuneitropism, electrotropism and rheotropism. In particular we will show that topological defects, known as dowsons or monopoles, can be manipulated by means of these tropisms.
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http://dx.doi.org/10.3390/ma13204681 | DOI Listing |
Materials (Basel)
October 2020
Departamento Ciência dos Materiais, CENIMAT, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
Due to its low symmetry C2v, the dowser texture is characterised by a 2D unitary vector field or alternatively by a unitary complex field. For the same symmetry reasons, the dowser texture is sensitive, in first order, to perturbations such as thickness gradients, electric fields or flows. We will focus on corresponding properties called respectively: cuneitropism, electrotropism and rheotropism.
View Article and Find Full Text PDFEur Phys J E Soft Matter
June 2019
CENIMAT, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829 - 516, Caparica, Portugal.
Due to its low symmetry, the long-lived pseudo-planar texture, dubbed "the dowser texture", has a flexo-electric spontaneous polarisation [Formula: see text]. Being degenerated, the dowser texture is easily aligned by the electric torque [Formula: see text] acting on [Formula: see text]. The dowser texture can also be aligned by Poiseuille flows driven by electro-osmosis.
View Article and Find Full Text PDFSoft Matter
February 2019
Laboratoire de Physique des Solides, Université Paris-Sud, 91405 Orsay, France.
The persistent quasi-planar nematic texture known also as the dowser texture is characterized by a 2D unitary vector field d. We show here that the dowser texture is sensitive, in first order, to electric fields. This property is due to the flexo-electric polarisation P collinear with d expected from R.
View Article and Find Full Text PDFEur Phys J E Soft Matter
December 2017
CENIMAT, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516, Caparica, Portugal.
In spite of its metastability, the pseudo-planar texture of a nematic layer confined between surfaces with homeotropic anchoring can be preserved indefinitely in certain conditions. The pseudo-planar texture, dubbed "the dowser texture", is degenerated and therefore sensitive to perturbations. It has been shown recently that the dowser texture is cuneitropic, that is to say, has a tendency to follow thickness gradients.
View Article and Find Full Text PDFEur Phys J E Soft Matter
December 2016
Laboratoire de Physique des Solides, Université Paris-Sud, Bât. 510, 91405, Orsay, France.
We show how to easily generate point defects called hedgehogs, in the so-called quasi-planar texture --the dowser state-- of a nematic layer confined between surfaces with homeotropic anchoring conditions. We point out that the dowser texture can be preserved infinitely in spite of its higher energy with respect to the homogeneous homeotropic texture. For topological reasons the dowser state in a squeezed droplet must contain at least one hedgehog.
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