The general character of dynamic transitions of colloids have attracted the attention of a vast part of the soft matter community, since achieving the on-the-fly control of colloidal states, from solid to liquid and vice versa, is a possible path towards “smart” materials with switchable properties.In this context, the “contamination” of colloidal suspensions with smaller particles or polymers has been one of the most adopted strategies to tune colloidal dynamics and explore the possibility to tailor new materials. However, despite their importance to understand the fundamental behavior of soft matter, all model systems (like model hard spheres) employed up to now to investigate such transitions are quite uncommon in nature, since they disregard the effect of charges on both colloids and (non-adsorbing) “contaminants”. Indeed, all colloids and polymers dissolved in polar solvents, such as water, very often bear ionizable groups. In aqueous solutions, for example, polyelectrolytes (PE) and oppositely charged colloids, due to electrostatic interactions, self-assemble into complex aggregates. Although PE-colloid complexation has been observed in a variety of mixtures under different conditions, in all reported studies the surface charge density of the colloids was fixed, or, at least, it could not be changed without changing the chemistry of the suspending medium, limiting to a large extent the on-the-fly control of PE adsorption. Recently, I and my coworkers [Soft Matter 14, 4110 (2018)] have shown that ionic colloids with stimuli-responsive charge density, like PniPam microgels, give the opportunity to tune finely the adsorption of oppositely charged species simply by modulating the stimulus concerned, i.e. temperature. This opens a new route to trigger PE or nanoparticle (NP) adsorption onto microscopic soft substrates, to tailor the structure and the dynamics of soft binary ionic mixtures and to remove ionic contaminants in a controlled manner. These issues represent the core of THELECTRA. In particular, this action aims at investigating how electrostatic adsorption of charged polyelectrolytes (PE) affects the structure and the rheology of oppositely charged ionic microgel suspensions, and to use the latter as eco-friendly adsorbent flocculants, i.e. as systems capable to adsorb physically a wide class of ionic wastes. I will investigate for the first time the state diagram of PE-microgel complexes in terms of rheology and microscopic dynamics, by doping dense and dilute microgel suspensions with model nano-contaminants (PE). We will use a set of complementary experimental techniques, including a unique rheo-light scattering setup, to determine the microscopic dynamics of PE-microgel complexes formed at high concentrations, both at rest and under large shear deformations. This will allow measuring the rheological response and the microscopic dynamics of concentrated suspensions at different PE concentrations and across fluid-solid transitions. A quantitative comparison between the microscopic dynamics (e.g. mean square displacement and dynamic structure factor) and macroscopic mechanical properties (e.g. elastic and viscous moduli) of microgel-PE suspensions will be performed. This will elucidate the microscopic origin of their rheological properties, including yielding, ageing and possibly thixiotropy. Such a fundamental understanding will be utilized to provide a robust proof of concept for a fully functioning water treatment cell for grey water purification. Taking advantage of the thermosensitive charge density of microgels, waste encapsulation at high temperature (T>33°C) results in the formation of reversible large aggregates that are easily filtered, while microgels can be recycled for successive remediation cycles. THELECTRA is the first attempt to use PniPam microgels for wastewater remediation on their own (i.e. when they are not involved in a composite material) by exploiting their electrostatic properties.