SOFTEVA · Drying of complex fluids on soft substrates

The study of soft materials has received a growing attention in last decades.Broadly speaking, these materials present viscoelastic properties giving them the ability to be highly deformable.Recently, new interests have been found in the wetting of soft deformable surfaces because of the many applications in material science, chemistry and biology for cosmetics, medicine, new printing technologies...On the other side, significant results has been obtained on the drying of complex fluids composed of a volatile solvent and solid particles, like the drying of a coffee drop resulting in a remarkable coffee stain effect.These studies generally involve non-deformable surfaces.Our project aims to bring together, for the first time, these two topics independently studied in the litterature.The proposal consists in an experimental study of the drying of a colloidal drop on deformable gels of different properties: elasticity, viscoelasticity and swelling.The objective is to describe the impact of gel mechanical properties on the drying process, contact line dynamics, resulting deposit shape and crack patterns.The proposed research will provide an overview of expected drying regimes as a function of substrate properties.This study will be completed with a theoretical analysis of the experimental results to provide complementary insights on observed phenomena.Moreover, applications, toward biology in particular, will retain our attention throughout the whole project since the returning host institution is active on this subject.The fellow will benefit from hosts expertise on gel chemistry and theoretical modeling to attain a leading independant position.The outgoing host is an expert in elastocapillarity and the return host in contact line dynamics and coating.""