MSCA COFUND PhD@Tec21 - PhD position in Soft Matter From Soft Cells to Solid Cellular Matter: Programming Structure via Drying Dynamics

Doctorat / PhD Profil chercheur : First Stage Researcher (R1) Type de contrat : Temporary Date limite de candidature : 28 Feb 2027 - 13:00 (Europe/Paris) Date de début : 1 Oct 2027 Programme UE : Horizon Europe – COFUND Département : COFUND PhD_at_Tec21 Domaine : Physics

Context and work environment Solid cellular materials derive many of their functional properties from their architectures, such as for adaptive stiffness, mass transport, and energy dissipation. Existing fabrication approaches, including additive manufacturing and templating, provide a good control over cellular structures. However, these strategies generally require pre-designing or imposing structures in advance, meaning that any change in the desired properties needs redesigning the underlying architecture. This project explores a different strategy: Can cellular structures self-emerge and be controlled during material processing, without being pre-designed or imposed? Inspired by the self-organization in emulsions and liquid foams, we will apply hydrogel foams as the model system and investigate how cellular architectures evolve during drying. Here, drying is more than simply removing water: it is a dynamic transformation in which water transport, capillary forces, and the network mechanics interact to shape the final structures. The project will address how do these coupled dynamics govern the structure selection and whether they can be translated into predictive design rules. Team description The PhD Fellow will primarily work within two Tec21 associated laboratories in Grenoble, and will also benefit from the research secondment in Amsterdam. Laboratoire Rhéologie et Procédés (LRP) has strong expertise in rheology, complex fluids, soft materials, and process engineering. The lab provides access to rheometers and a spinning-disk fast confocal microscope. Laboratoire Interdisciplinaire de Physique (LIPhy) conducts multidisciplinary research in physics, with particular expertise in foam rheology, bubble dynamics, and soft matter physics, hosting a microfluidic fabrication platform. Institute of Physics, University of Amsterdam (UvA) provides the secondment training for the Fellow, and offers access to the advanced high-speed imaging. The PhD Fellow will be jointly supervised by Kaili Xie (LRP, CNRS) and Benjamin Dollet (LIPhy, CNRS), with additional guidance from Hugues Bodiguel (LRP) and Daniel Bonn (UvA). The team brings complementary expertise in capillarity-driven dynamics, complex interfacial phenomena, and rheology. The team provides a strong scientific and technical environment for the development of the project and broad training opportunities in experimental soft matter. Description of the project The hypothesis of the project is that the final cellular architecture is selected by the competition between capillary stresses, fluid transport, and network deformation in hydrogel foams, which can be tuned through drying pathways. To test it, the project will take a bottom-up approach, from well-controlled hydrogel films to 2D hydrogel foams, following the route: mechanism ® prediction ® design rules. Several research axes will be explored: Development of a hydrogel film model system. A free-standing hydrogel film platform will be constructed, based on microfluidics, to represent the local geometry in foams. Different gelation mechanisms, including ionic, covalent, and physical crosslinking, will be investigated. Interfacial rheometry will be used to characterize the mechanical properties of hydrogel films during drying. Identification of film evolution and rupture regimes. Based on free-standing films, we will apply fast confocal microscopy and high-speed imaging to probe when and where holes nucleate, grow, or arrest under controlled drying. These dynamics will be linked to evolving film rheology for identifying the mechanisms and rupture regimes. Establishment of predictive design rules. We will move from individual films to 2D foam structural evolution during drying. Neutron scattering and X-ray tomography (in collaboration with ILL) will be used to quantify water transport pathways and explore how they affect the structures. We will then establish predictive design rules for controlling the transformation of hydrogel foams into solid cellular materials. Supervisors: Kaili Xie, Benjamin Dollet Research fields: soft matter physics, fluid transport, drying dynamics, hydrogels, foams, cellular materials Secondment (academic partner): Institute of Physics, University of Amsterdam, the Netherlands Doctoral school: I-MEP2 Engineering – Materials, mechanics, environment, energy, processes, production

Context and work environment

Solid cellular materials derive many of their functional properties from their architectures, such as for adaptive stiffness, mass transport, and energy dissipation. Existing fabrication approaches, including additive manufacturing and templating, provide a good control over cellular structures. However, these strategies generally require pre-designing or imposing structures in advance, meaning that any change in the desired properties needs redesigning the underlying architecture.

This project explores a different strategy: Can cellular structures self-emerge and be controlled during material processing, without being pre-designed or imposed? Inspired by the self-organization in emulsions and liquid foams, we will apply hydrogel foams as the model system and investigate how cellular architectures evolve during drying. Here, drying is more than simply removing water: it is a dynamic transformation in which water transport, capillary forces, and the network mechanics interact to shape the final structures. The project will address how do these coupled dynamics govern the structure selection and whether they can be translated into predictive design rules.

Team description

The PhD Fellow will primarily work within two Tec21 associated laboratories in Grenoble, and will also benefit from the research secondment in Amsterdam.

Laboratoire Rhéologie et Procédés (LRP) has strong expertise in rheology, complex fluids, soft materials, and process engineering. The lab provides access to rheometers and a spinning-disk fast confocal microscope.

Laboratoire Interdisciplinaire de Physique (LIPhy) conducts multidisciplinary research in physics, with particular expertise in foam rheology, bubble dynamics, and soft matter physics, hosting a microfluidic fabrication platform.

Institute of Physics, University of Amsterdam (UvA) provides the secondment training for the Fellow, and offers access to the advanced high-speed imaging.

The PhD Fellow will be jointly supervised by Kaili Xie (LRP, CNRS) and Benjamin Dollet (LIPhy, CNRS), with additional guidance from Hugues Bodiguel (LRP) and Daniel Bonn (UvA). The team brings complementary expertise in capillarity-driven dynamics, complex interfacial phenomena, and rheology. The team provides a strong scientific and technical environment for the development of the project and broad training opportunities in experimental soft matter.

Description of the project

The hypothesis of the project is that the final cellular architecture is selected by the competition between capillary stresses, fluid transport, and network deformation in hydrogel foams, which can be tuned through drying pathways. To test it, the project will take a bottom-up approach, from well-controlled hydrogel films to 2D hydrogel foams, following the route: mechanism ® prediction ® design rules. Several research axes will be explored:

Development of a hydrogel film model system. A free-standing hydrogel film platform will be constructed, based on microfluidics, to represent the local geometry in foams. Different gelation mechanisms, including ionic, covalent, and physical crosslinking, will be investigated. Interfacial rheometry will be used to characterize the mechanical properties of hydrogel films during drying.

Identification of film evolution and rupture regimes. Based on free-standing films, we will apply fast confocal microscopy and high-speed imaging to probe when and where holes nucleate, grow, or arrest under controlled drying. These dynamics will be linked to evolving film rheology for identifying the mechanisms and rupture regimes.

Establishment of predictive design rules. We will move from individual films to 2D foam structural evolution during drying. Neutron scattering and X-ray tomography (in collaboration with ILL) will be used to quantify water transport pathways and explore how they affect the structures. We will then establish predictive design rules for controlling the transformation of hydrogel foams into solid cellular materials.

Supervisors: Kaili Xie, Benjamin Dollet Research fields: soft matter physics, fluid transport, drying dynamics, hydrogels, foams, cellular materials Secondment (academic partner): Institute of Physics, University of Amsterdam, the Netherlands Doctoral school: I-MEP2 Engineering – Materials, mechanics, environment, energy, processes, production

Where to apply Website https://phd-at-tec21.sciencescall.org/