Dynamics and Self-Organization of Deposits at Liquid-Solid Interfaces: Towards Stable Functional Surfaces under High Heat Fluxes (M/F)

Job Description

Thesis Subject

When a droplet containing a solute evaporates on a surface, it leaves behind a characteristic ring-shaped deposit known as the “coffee-ring effect.” This everyday phenomenon, although seemingly trivial, results from complex physicochemical mechanisms in which evaporation, internal flows, mass transport, and solidification lead to the spontaneous organization of matter near the triple contact line—the region where solid, liquid, and gas meet. Numerous applications exploit this effect in the field of functional materials (self-assembly of solid particles, inkjet printing of transparent conductors, pattern formation through self-organization, colloidal crystals, quantum dots, etc.), in biological sciences (medical diagnostics such as blood analysis, food quality control, environmental pollutant monitoring), and in spray-based de-icing and surface cooling (heat exchangers, heat pipes).
Particularly for the latter application, the interfacial properties of surfaces (wettability, surface energy, roughness) govern heat transfer efficiency. However, under intense thermal flux and repeated contact with fluids, these surfaces may degrade, accumulate deposits, and finally lose the properties for which they were initially designed. Gaining a deeper understanding of the mechanisms responsible for this degradation is therefore a major challenge for ensuring the durability of systems subjected to repeated high heat fluxes
Thus, the liquid–solid interface, and especially the triple contact line, can no longer be considered as a passive boundary. It becomes an active microscopic region, similar to a micro-reactor, where transport phenomena, physicochemical transformations, and interfacial dynamics are strongly combined. Indeed, the solid deposits that form within this region, in turn, feed back on the flow, heat transfer, and surface properties, thereby amplifying their evolution over time.
The objective of the PhD project is to understand how these deposits form locally, organize, and affect the durability of functional surfaces. The work will progressively investigate the underlying mechanisms, from quasi-stationary situations to highly dynamic and far-from-equilibrium regimes, such as droplet impact. By exploring these phenomena, the project aims not only to control the local structuring of matter but also to guide self-organization processes, paving the way for the design of durable functional surfaces optimized for extreme conditions.

The PhD candidate will be responsible for designing and conducting experiments using optical and thermal diagnostics (infrared imaging, laser-induced fluorescence, high-speed imaging, shadowgraphy), as well as multi-scale surface characterization techniques (SEM, optical profilometry, XRD, TEM, XPS).The candidate will also collect and analyze experimental data in order to propose physical interpretations and identify the underlying mechanisms. A progressive experimental strategy will be followed to study the formation of deposits and their impact on transport phenomena, starting from quasi-stationary configurations (fed liquid films), then moving to slowly evaporating sessile droplets, and finally to dynamic droplet situations.

Skills :
- Master's degree or Engineering degree in physical chemistry or materials science and engineering, ideally with a specialization in interfacial physico-chemistry.
- Knowledge of transport phenomena (heat transfer, fluid flow) is appreciated.
- Ability to work in an interdisciplinary and multi-team research project.
- Ability to adapt to two complementary research environments.
- Proficiency in French and/or English

Your Work Environment

The PhD candidate will work across two sites: the Institut Jean Lamour (ARTEM campus) and LEMTA (Brabois campus), with regular travel between them. A personal office will be provided at each location.

About Institut Jean Lamour :
The Institute Jean Lamour (IJL) is a joint research unit of CNRS and Université de Lorraine.
Focused on materials and processes science and engineering, it covers: materials, metallurgy, plasmas, surfaces, nanomaterials and electronics.
By 2026, IJL has 258 permanent staff (33 researchers, 133 teacher-researchers, 92 IT-BIATSS) and 389 non-permanent staff (146 doctoral students, 43 post-doctoral students / contractual researchers and more than 200 trainees), from some seventy different nationalities.
Partnerships exist with 150 companies and our research groups collaborate with more than XX countries throughout the world.
Its exceptional instrumental platforms are spread over 4 sites ; the main one is located on Artem campus in Nancy.

About LEMTA :
The Laboratory of Energy and Theoretical and Applied Mechanics (LEMTA) is a joint research unit of CNRS and the University of Lorraine, affiliated with the CNRS Institute for Engineering and Systems Sciences (INSIS). It specializes in energy, mechanics, and transport phenomena, covering fluid mechanics, heat and mass transfer, energy systems, physico-chemistry of flows, complex media, and processes. LEMTA includes around 80 researchers and faculty members, 30 technical and administrative staff, and approximately 80 PhD students and postdoctoral researchers. Its experimental and numerical activities rely on advanced instrumental platforms.

Constraints and risks

-

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

The research professions