The function of vascular plants relies both on active and passive transport phenomena driven through two coupled vascular systems: transpiration moves water from the roots to the leaves through the xylem to maintain hydration and transfer nutrients, and osmosis drives the flow through the phloem carrying photosynthesized sugars from the leaves throughout the plant for growth and storage; both of these flows are also hypothesized to mediate long-distance biochemical signaling within the plant. Many fundamental questions remain on the physiological mechanisms of operation and functional roles of these transport processes, particularly relative to the phloem and its coupling to the xylem and other tissues: 1) the biophysics of the loading and unloading of sugars, water, and signaling molecules to and from the phloem; 2) the dynamics of phloem transport as a function of biotic (e.g., photosynthetic rate and localized tissue growth) and abiotic (e.g., diurnal variations in water status) processes; and 3) the coordination of these processes at the whole-organism scale. Progress on these topics has been hindered by the lack of experimental tools with which to investigate hypotheses across scales, from local membrane-mediated to system-scale processes, either in vitro or in planta. In this project, we will bring together expertise on physicochemistry, device engineering, and plant biology to develop new approaches to address these questions. The team will: 1) develop the first synthetic system that allows for recapitulation of the full, coupled operation of the xylem and phloem systems; 2) use this platform to test a diversity of biophysical hypotheses on the mechanisms and function of plant vasculature; and 3) inform and confront in vitro experiments with biophysical and biochemical experiments in vivo. This effort will provide new insights into the biology and biophysics of plant vascular function and create new tools for basic and applied research by others.

In the general framework of coatings performed by deposition of a liquid film on a substrate and evaporation of a volatile solvent in air, this proposal focuses on geometries with a moving contact line or a meniscus. It concerns specific situations corresponding to small substrate velocities, when significant evaporation takes place in the meniscus and impacts the flow (evaporative regime in dip-coating-like configurations). It addresses the general question of the impact of flow dynamics and heat/mass transfers, on the dry deposit obtained during the evaporative coating. The main objectives are to get an in-depth knowledge and understanding of the dominant phenomena, and to get quantitative predictions, to infer the coating process parameters needed to get the required specifications of the dry deposit. Both experimental and modeling approaches are planned to fulfill these objectives. Innovative experiments will be developed to measure simultaneously the concentration field along the moving meniscus (from the initial dilute solution/dispersion up to the dry deposit) and the corresponding velocity field (one set-up on a microscope platform, with PIV measurements and spectroscopic Raman measurements). Experiments will be performed on the one hand on model systems (polymer solutions and nanocolloidal dispersions). A throughout characterization of the system properties will be preliminary performed. Indeed, a specific point in such coating processes is the strong evolution of the physico-chemical properties of the complex fluid during drying, such as the viscosity, surface tension or mutual diffusion coefficient, and the transition from a liquid to a solid state (for instance the formation of a porous medium in the case of colloids). Besides investigations of model systems, we propose to focus one part of our efforts through this program in the wide field of Organic Electronics (e. g. OLED Organic Light Emitting Diode, OPV Organic PhotoVoltaics), and two R&D scientists of Solvay are involved in this proposal. From the modeling point of view, and following previous works, a first challenge will be to develop dynamical models taking into account the hydrodynamics in the meniscus, the coupling with the gas phase, and including the concentration dependent properties of the system. The objective is to describe (and then predict) the impact of hydrodynamics in the bulk and meniscus on the dry deposit. It will concern especially the following questions: may hydrodynamics and mass transfer explain the occurrence of a periodic regime that induces the formation of regular patterning on the dry film (stick-slip)? Which phenomena drive this periodic regime? (presently an unsolved question). The other theoretical part concerns the evaporative coating of colloids leading to the building and the consolidation of a dense porous medium. Many fundamental questions are still open for the description of the transition from the liquid phase to the final film, and it will be one of the issues of this proposal to go further in such description. To perform such a challenging task, we propose to use continuous models describing the transition from the dispersed state up to the dense colloidal assembly through continuous models but showing a divergence at the close packing transition (such as the mutual diffusion coefficient, the osmotic pressure, the viscosity, etc). One challenge of our approach is to apply such existing models to the evaporative coating regime for which flow and mass transfers occur simultaneously and finally to get a complete model taking into account the hydrodynamics and the liquid/porous transition and able to describe the whole process.

This project deals with micro-assembly in the mesoscale between micro and nanoscales, which comprises objects whose size is from 100nm to 10µm. It addresses several scientific problematics, in the domains of microfluidics, micro-nanorobotics and nanojoining. This topic presents an applicative interest for next generation of nanotechnological components. Indeed, despite a large number of proofs of concept of elementary functions (e.g. chemical, biomedical or environmental sensors) in nanotechnologies, related nano electromechanical systems (NEMS) hardly come to the market. One of the bottlenecks is the packaging of these new components whose dimensions are around the micrometer. As for micro electromechanical systems (MEMS) where packaging is based on robotic microhandling, the packaging of NEMS requires to be able to handle, position and join components together. Current industrial state of the art is limited to the assembly of hundred microns scale dies which is inappropriate for nanotechnologies which is able to provide components hundred times smaller. This project will provide innovative methods to perform assembly of components in the mesoscale between micro and nanoscales in order to open new ways in packaging for nanotechnologies. In a scientific point of view, mesoscale represents a paradigm in assembly methods : this mesoscale assembly is situated between nanoscale and microscale assembly, which are two completely different processes. On the one hand, self-assemblies (chemical reactions) have been used for decades to build assembled nanocomponents. On the other hand, microassemblies in industry are mainly based on robotic handling and positioning. Mesoscale represents a crossroad between these two approaches, where scientific studies are required to provide ad hoc solutions for this particular scale. We propose to study some hybrid approaches based on directed self-assembly, which is based on physical effects (non- contact forces) usually used in self-assembly, but also on active trajectory control inspired from robotics. As self-assembly is mostly performed in liquid, we will perform directed self-assembly in liquid channels, also used to convey components. Objects will be positioned by non contact forces, and joined with original nanojoigning methods. Consequently this project is divided in three technical workpackages respectively on (i) the study of fluidic transfer of mesoscaled objects in microchannels; (ii) the study of objects positioning based on non-contact forces and (iii) the study of ad hoc nanojoining methods. These methodologies will be implemented in a final demonstrator in the fourth workpackage. A special attention will be paid to the management of the project in a last workpackage. The methods developed in the project will enable the assembly of mesoscale objects into stacks, to get different sensing capabilities integrated into the same component. They will also provide original ways to realize wire connection at the mesoscale. This project thus directly addresses the main issues of nanopackaging. This project relies on the internationally recognized partners. FEMTO-ST in Besançon and ISIR in Paris have top level expertise in micro-assembly and non-contact micromanipulation. They have successfully collaborated in the previous years on several ANR projects (ANR PRONOMIA, ANR NANOROL, EQUIPEX ROBOTEX). This consortium also includes the LOF which has a strong knowledge and international expertise in microfluidic. This multidisciplinary consortium has been built to tackle the complex scientific challenges proposed in this project. This project will provide new assembly methodologies in mesoscale in the framework of nanotechnology packaging. It is a first crucial step in the advent of industrial assembly methods in mesoscale which could be followed by a more applicative project supported by ‘ANR Emergence framework’ in order to prepare the transfer in the two years following this project.

Acoustic Metamaterials constitute a new and promising generation of materials whose unconventional characteristics, based on "exotic" values of their acoustic index (from 0 to infinity, imaginary, even negative), open the way to many advanced applications such that wave-field spatial control (for high-resolution imaging and beamforming), ultra-absorption and cloaking (for insulation and stealth). Among all classes of metamaterials, the locally resonant metamaterials take advantage of low-frequency resonances of "small" inclusions. Thanks to those local resonators these metamaterials allow the full control of long-waves while keeping a small size (sometimes very small), giving rise to the name of "sub-wavelength" metamaterials. At that time, there is a great deal of interest for applications with those acoustic materials especially for insulation in the audible domain and for stealth in underwater acoustics. Also, but with probably a lower societal and strategic pressure, the issues for ultrasonic instrumentation and imaging are potentially significant. Nevertheless acoustic metamaterials are still mostly at the stage of conceptual objects of laboratory. The route of soft-matter techniques opens up many ways of designing and fabricating new materials thanks to their great variety of processes and to the physical/chemical properties of the involved constituents (polymers for instance). Turning to good account our recent successful developments of macro-porous resonators (polymeric foam micro-beads), which are a key-element for acoustic metamaterials, we are at the stage where we can envisage the making of many different types of metamaterial-based devices relying on a large range of index-values (now experimentally available). This proposal is a strongly multi-disciplinary project between three labs in Bordeaux, expert in wave-physics, soft-matter and microfluidics. The consortium has more than 5 years of experience in joint-research on the topic of soft-metamaterials. This long collaboration coupled to the geographical proximity and the developed complementary skills is a key-point for challenging both the material and the acoustic aspects of the project. The Material challenge is to develop a new class of acoustic coatings based on the metamaterials concept, which are easily processable and up-scalable. First the meta-matter can be a fluid-based dispersion like paint and turned afterwards into solid-but-soft coating upon polymerization over a large variety of surfaces. Second, the meta-coating can be structured by using soft-lithography and shaped by molding. In that project the possibilities for the resonators synthesis and their structuring into a metamaterial-device are quite vast. The Wave-Physics challenge concerns the design and the experimental proof of targeted functions of several demonstrators. The chosen functions, in connection with further breakthrough technologies, deals with first: sub-wavelength absorption in the context of insulation and stealth; and second: wave-field spatial control for beamforming/front-shaping and cloaking. The flow scheme of BRENNUS is the following: 1. Chemistry and synthesis of micro-resonators according to some criterions (size, shape, high calibration, surface treatment, mass production...) and formulation of the host matrix; 2. Structuring and shaping metamaterials using soft-matter techniques in order to achieve paint-like raw metamaterial, flexible coatings and molded structures; 3. Realization of three types of demonstrators: a. Sub-wavelength meta-coating for sound insulation and stealth b. Transducer caps for beamforming in ultrasonics c. Anisotropic meta-layers for cloaking structures

Micro rheology is a field in which the study of viscoelasticity of materials serves to consider how their dynamic behavior changes with length scale. Applied to complex fluids, this field is of extreme industrial importance: from paints to foods, from oil recovery to processing of plastics, understanding the flow of complex fluids is essential to a wide range of technologies. The microrheology of complex systems still faces significant challenges: 1) in situ measurements within confined systems; 2) on line measurements in dynamic microsystems, and 3) viscosity mapping at the nanoscale. Microrheology is closely connected to the field of microfluidics, which considers phenomena such as those involved in ink jet printing, 3D printing, microelectrophoresis on a chip, microvalves and the kinetics of protein crystallization. The overlap is thus quite strong and the fluid mechanics of materials in confined geometries is a common area to the two research fields. The dynamics and the microrheological behavior of confined fluids often change dramatically when, for instance, they are confined near a surface. The interfacial characteristics of gas, liquid and solid interfaces all require individually optimized methods for the measurement of the surface microrheology. Even more, traditional mechanical viscometers are not able to measure viscosity of microsystems and, more important, they cannot measure microviscosities in real-time conditions or perform time- and spatially-resolved mapping of the microviscosities in confined systems. MICROVISCOTOR proposes an innovative strategy to develop a cost-effective microfluidics device capable to measure and map on-line and in real-time spatially- and time-resolved microviscosities of fluids by using molecular rotors. The strategy presented here is applied to microfluidic processes with the aim to develop low-cost “lab on a chip” devices or sensors.