The “Plastics, Environment and Health” research network (groupement de recherche, GDR) created in 2019 gathers the French scientific community working on plastic pollution in all environments (soil, air, water) and their impact on ecosystems and human health. The scientific objective is to rapidly increase knowledge on plastic pollution by supporting collaboration of researchers from different fields such as ecotoxicology, chemistry, physics, microbiology, oceanography and social science. Research is carried out at each stage of the plastic life cycle, (from resource extraction all the way to removal and remediation) and across the entire air-soil-water continuum, integrating transfers of both plastic particles (macro, micro- and nanoplastics) and plastic chemicals (e.g., additives) between different environmental compartments. In this context, the GDR supports the development of multi-scale and transdisciplinary approaches across three main axes: Axis 1 - Air-soil-water continuum: contamination levels and transfer between compartments; Axis 2 - Interactions and transformation of plastics in environmental compartments and living organisms; Axis 3. Plastic pollution risk assessment for ecosystems and human health. To do so, the GDR’s actions focus on (1) training and sharing of scientific knowledge, including developments towards innovation, (2) support for collaboration and interdisciplinarity between network members, (3) dissemination, structuring of the community and its national and international influence, and (4) support for public policy and/or decision-making by strengthening the link between scientists, decision-makers and the plastic industry. To date the research network includes more than 50 laboratories spread across France and over 300 scientists in the field of physics, chemistry, biology, ecology and social sciences. Such a network constitutes a powerful tool to build robust science-based knowledge significantly contributing to the international effort, to disseminate state-of-the-art scientific advances and research priorities needed to tackle plastic pollution to Society and to inform policy makers. This talk will present the French taskforce addressing 'Plastic, Environment, and Health' within the national research network, where the entire community works collaboratively to tackle the urgent challenges of plastic pollution, its environmental consequences, and the associated risks to human health. We will also discuss the importance of building a French-speaking community to support multilingualism in international political science interactions.

This chapter addresses scattering from suspensions of interacting colloids at finite concentrations, from both a theoretical and an experimental perspective. We start in Section 2 by describing the main effective interactions arising in colloidal systems: excluded volume effects as in hard particle suspensions, electrostatic contributions due to charge dissociation and release of counter-ions, and depletion interactions. We then discuss in Section 3 the Ornstein–Zernike equation, which allows one to calculate the radial distribution function and static structure factor directly from the interaction potential, by using a so-called closure relation. After introducing the most popular closures, we examine their predictions for the equation of state and the problem of thermodynamic consistency. We then briefly tackle the extension of the treatment to mixtures and polydisperse particles. Next, in Section 4 we introduce the ideal Mode-Coupling Theory of the glass transition, a microscopic theory that allows one to predict dynamics solely from the knowledge of the structure. In Section 5, we discuss the main experimental challenges that arise in scattering studies of non-ergodic systems, for which the usual time average performed in experiments does not yield the desired ensemble average. Various schemes proposed for collecting ensemble-averaged data are presented, including multi-speckle methods that allow for time- and space-resolved dynamic light scattering. In Section 6, we illustrate the concepts presented in the first part of the chapter by presenting some key experimental results for colloidal glasses and gels. We start by discussing repulsive hard and soft glasses. Then, we focus on short-ranged attractive colloids and discuss them in the context of attractive glasses as well as gels, highlighting the comparison between theoretical predictions and experimental results. In the final section, we draw some conclusions and make remarks for future work.