Shape and stress relaxation in gelling droplets

Encapsulation is a process that enables to protect, transport and deliver active species in dedicated areas. One encapsulation process is the alginate/calcium dripping method, where droplets of a biopolymer, alginate are dripped on a calcium bath where the calcium ions diffuse into the polymer droplets and bind the molecules together to obtain a hydrogel bead. We investigate the shape relaxation of these gelling droplets. We show experimentally and numerically that a gelled layer grows at the surface. Due to volume contraction of the gelling shell, this layer induces tensile stresses and drives a ow in the ungelled liquid core, resulting in the relaxation of the droplets toward spherical shapes. Over time the thickness of this elastic membrane grows hence the bending stifness required to change its shape eventually balances the surface stresses, which arrests the relaxation process.
These results provide general rules to understand the shape of solidifying materials combining both tension and bending driven deformations.

Godefroid, J., Marcellan, A., Bouttes, D., Barthel, E., and Monteux, C., Soft Matter, 2023


Top



See also...

Un doctorant du SIMM, Julien Es Sayed, lauréat du Prix de la Diffusion de la Recherche Jean Langlois

Le 15 juin dernier, le comité de sélection Jean Langlois a décerné le prix de Diffusion de la Recherche à Julien Es Sayed, doctorant du SIMM pour ses (...) 

> More...

Quantifying Molecular Damage during Elastomer Fracture

When rubbery materials (elastomers) are stretched, they typically extend elastically and spring back to their original shape. However, if (...) 

> More...

 

Practical information

Sciences et Ingénierie de la Matière Molle

Soft Matter Sciences and Enginering - UMR 7615

10 rue Vauquelin
75231 PARIS CEDEX 05
FRANCE

  • Chair : E. Barthel
  • Steering Committee : J.B. d’Espinose, A. Chateauminois, Y. Tran, B.Bresson
  • Administration : F. Decuq & Odile Neveu
  • Communication : A. Hakopian & M. Ciccotti
  • Information Technology : A. Hakopian
  • Safety, Health and Environment Assistant : F. Martin & M. Hanafi

Getting here
Legal notes