Invagination during the collapse of an inhomogeneous spheroidal shell

¹ Laboratoire Fluides, Automatique, Systèmes Thermiques (associé au CNRS et aux Universités Paris 6 et Paris 11) Bâtiment 502, Campus Universitaire d'Orsay, 91405 Orsay Cedex, France
² Laboratoire de Physique Statistique (associé au CNRS et aux Universités Paris 6 et Paris 7) Ecole Normale Supérieure - 24 rue Lhomond, 75231 Paris Cedex 05, France

Corresponding author: pauchard@fast.u-psud.fr

Received: 7 August 2003
Accepted: 12 March 2004

Abstract

The collapse of shell-shaped membranes due to buckling is investigated experimentally using droplets of latex suspension left to dry. The evaporation of water, limited by diffusion in air, first leads to the formation, on the surface, of a spheroidal envelope of gel. During the later evolution, spontaneous buckling of this envelope occurs. The later evolution leads to a large-amplitude invagination and for certain concentrations to a transition to a toroidal shape. This specific evolution of a spheroidal envelope, linked with its inhomogeneous mechanical properties, is similar to that observed during the gastrulation of sea-urchin embryos.