Eur. Phys. J. E (2016) 39: 89
https://doi.org/10.1140/epje/i2016-16089-2

Regular Article

Hygroscopic study of hydroxypropylcellulose

Structure and strain-induced birefringence of capillary bridges

¹ CENIMAT - Centro de Investigaçao em Materiais, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa Campus da Caparica, 2829 - 516, Caparica, Portugal
² Laboratoire de Physique des Solides, UMR 8502, Université Paris-Sud, Bât. 510, 91405, Orsay, France
³ Laboratoire Polymères et Matériaux Avancés, CNRS/Rhodia-Solvay, UMR 5268, 87 avenue des Frères Perret, 69192, Saint Fons, France

^* e-mail: pawel.pieranski@u-psud.fr

Received: 3 June 2016
Accepted: 8 September 2016
Published online: 29 September 2016

Abstract

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 n is measured as a function of the draw ratio . The variation of n with is interpreted in terms of an affine uniaxial deformation of the initial pseudo-isotropic texture.