Hygroscopic study of hydroxypropylcellulose : Structure and strain-induced birefringence of capillary bridges.
The hygroscopic method developed previously for studies of lyotropic liquid crystals is used for the first time in experiments with millimetric capillary bridges made of a hydroxypropylcellulose/water mixture. Composition of such very small samples is controlled via humidity of the surrounding air. By a slow and well-controlled drying of initially isotropic samples, the isotropic/anisotropic phase transition is crossed and polydomain pseudo-isotropic capillary bridges are prepared. Kept in an atmosphere of constant humidity, these bridges are stretched and the strain-induced birefringence [Formula: see text] n is measured as a function of the draw ratio [Formula: see text] . The variation of [Formula: see text] n with [Formula: see text] is interpreted in terms of an affine uniaxial deformation of the initial pseudo-isotropic texture.
CENIMAT - Centro de Investigaçao em Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa Campus da Caparica, 2829 - 516, Caparica, Portugal.
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MH
Godinho
Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, Bât. 510, 91405, Orsay, France. pawel.pieranski@u-psud.fr.
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P
Pieranski
Laboratoire Polymères et Matériaux Avancés, CNRS/Rhodia-Solvay, UMR 5268, 87 avenue des Frères Perret, 69192, Saint Fons, France.
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Sotta
Soft Matter: Liquid crystals