Janus particles, bearing two distinct compositions on the surface of the same particle, have attracted much attention recently as a way to finely tune morphology and functionality of colloidal particles, with potential applications ranging from building blocks for highly ordered structures to drug carriers. The aim of this proposal is to study the selective adsorption of poly(ethylene oxide) on Janus particles bearing hydrophobic (polystyrene) and hydrophilic (silica) surfaces. We have previously used SANS measurements to obtain detailed structural information on the volume fraction profile of polymer layers adsorbed on colloidal particle surfaces in both dilute and concentrated solutions. We propose here to describe the adsorption behaviour of PEO with varying silica/PS ratio on the Janus particles, using for this purpose a carefully selected set of contrast-matching conditions.