Expérimental
Formulated products from the pharmaceutical and food industries are often made up of mixtures of rigid particles, polymers of various architectures, or droplets. These complex systems can gel, i.e., form a percolated network that imparts viscoelastic solid behavior to the material, depending on the total colloid volume fraction and the nature of their physicochemical interactions. Understanding the gelling mechanisms of colloidal mixtures is important for controlling and predicting the rheological properties of many everyday products. In recent work, we have developed a model binary system involving soft colloids (polyacrylamide microgels, Am) and hard colloids (silica particles), with modular attractive interactions. A series of systems have been studied, successively exhibiting repulsive, attractive colloidal gel behavior and gelling by arrested phase separation by adding either a small amount of a "sticky" co-monomer to the microgels or a co-solvent, such as glycerol. The aim of this internship is to modulate the attractive interactions of this binary colloidal system via a "solvent" route. The state diagrams will be studied by formulating different mixtures to identify the gelling conditions and the behavior of these binary mixtures under concentrated flow. Next, the reinforcing effects of attractive interactions on rheological properties will be investigated.