Research project P7/38 (Research action P7)
Major objectives
Scientific objectives
Our scientific objectives are driven by fundamental questions raised in microfluidics, interfacial science, and micromanipulation. The possible use of surface tension and capillary effects in micromanipulation leads to a large variety of more practical problems studied by the network partners, such as capillary gripping, capillary filling, capillary alignment, capillary sealing, capillary self-assembly and droplet manipulation (incl. generation and transport).
As detailed in the project description, these fundamental questions can be grouped into three categories:
1. Fluid statics and dynamics: How much force is applied on solids by menisci and micro-flows in a given geometry? What happens if the solid bends when subject to these forces? Are the interfaces stable and what if not? What is the effect of an electric field? How can the microscopic description of wetting be translated into an adequate boundary condition at the macroscopic level (e.g. contact angle and hysteresis)?
2. Surface engineering: How does a contact line move on a rough surface? Can one pattern the surface microscopically to control this motion? How is the motion affected by evaporation, or by the presence of colloid particles in the liquid? Do these particles interact with the micro-patterns on the surface? Can one create highly 3D patterns on the surface by using capillary forces (e.g. to bundle nanotubes)?
3. Liquid engineering: How to measure the interfacial and bulk properties of complex liquids (eg. soap films)? How to infer macroscopic properties from the dynamics at the molecular scale? And how to engineer liquids and tailor them to the requirements arising from applications? Can one make a liquid which is biocompatible, and has a large surface tension and a low viscosity?
The proposed program is highly multidisciplinary, as it combines the forefront research in physics, material science, chemistry and engineering. It will cover topics that range from fundamental theory with atomistic simulations to fundamental experiments and applied research. It will address both static and dynamic points of view, and establish the link between the microscopic properties of liquids and surfaces, and the macroscopic performances expected in the case studies. To that aim, this IAP project has gathered a multi-disciplinary research team that covers all the disciplines listed above.
The originality of this proposal relies in the efforts to enhance the collaboration of both the interfacial science, microfluidics and microengineering communities.
Training and dissemination objectives
Particular attention will be given to the dissemination of results and training of students, both from and to the network. Dissemination from the network will be achieved by organizing workshops, while inviting host professors will serve the dissemination to the network. Training will include the organization of summer schools and doctoral programs based on existing lectures at our institutions. These activities are described in form N, Network management.
Young researchers will spend time in more than one of the participating teams. In this way, they will be confronted with a broad variety of approaches to the same class of phenomena. They will learn several techniques, be exposed to many different points of view, and they will have to combine the information from various sources into a single coherent picture. This will be further enhanced by the organization of frequent meetings (both bilateral meetings between closely collaborating teams, and plenary meetings of the entire network).
Besides this “internal” training, the network will have a strong international impact and a high visibility. Indeed, the proposed IAP program will be explicitly associated to current and future international research projects and collaborations.
Summary of research activities
The project falls into three major work packages: fluids statics and dynamics, surfaces and liquids engineering. Combining these perspectives will fruitfully lead to a significantly improved fundamental knowledge, and to the development of future applications in microtechnologies. The workpackages interact with each other to come to a coherent network of research. They are detailed in form D, detailed description of the proposal.
WP1 – Fluids statics and dynamics (i.e. how to describe both static and dynamic fluid flows and droplets?):
T1.1 Macroscopic description of capillary bridges: statics, dynamics, coupling and force applied on solids
T1.2 Electro-hydrodynamics, droplets and rivulets
T1.3 Elasto-capillarity
T1.4 Effective boundary conditions and contact lines
WP2 – Surfaces engineering (how to engineer solids and surfaces?)
T2.1 Relationship between contact line motion and surface texturing
T2.2 Synthetic self-assembly with capillary forces, including Cheerios effect
T2.3 Synthetic self-assembly through engineering liquid-liquid and liquid-surface interfaces
WP3 – Liquids engineering
T3.1 Liquids characterization
T3.2 Liquids modelling
T3.3 Liquids engineering
