Adsorption of nanoparticles at the solid-liquid interface

► We present an X-ray reflectivity study of a liquid-solid interface. ► Positively charged maghemite nanoparticles form a monolayer on a silica surface. ► Negatively charged gold nanoparticles are repelled from the interface. ► Logarithmic particle distribution functions are able to describe the layers profile. ► The stability of such adsorbed films against rinsing is demonstrated.