Tailoring the interfacial assembly of colloidal particles by engineering the mechanical properties of the interface

Fluid interfaces can be used as a platform for promoting the direct and spontaneous self-assembly of colloidal particles, where the driving force is the reduction in interfacial energy. In addition, fluid interfaces allow fine-tuning of the particles ensemble by an external force, such as the presence of an imposed interfacial flow, or by engineering the interparticle interactions dictated by the interplay of interfacial forces. As a consequence, a wide-ranging set of interfacial structures can be achieved from liquid-like layers, which can flow under stress, to amorphous solids that are able to sustain static stress. Here, far from a comprehensive overview of the interfacial assembly of colloidal particles, different ways of tailoring it by rationally designing the rheological properties of the interface are provided, with a focus on experimental and theoretical methods and model systems that have been recently exploited. In particular, ligand-coated nanoparticles, with a strong emphasis on the effect of the ligands on the interfacial structure and the rheological properties, and soft nanogel particles, in which an environmental factor, such as the temperature, drives to different interfacial structures and mechanical responses will be further discussed.