Pu(IV) is known to be highly prone to hydrolysis leading to the formation of extremely stable Pu(IV) colloidal suspensions (known as intrinsic colloids). The lack of knowledge concerning the speciation and reactivity of these Pu colloids hinders the development of reliable models allowing to predict their behavior in industrial and environmental systems. The behavior of these colloidal species towards dissolution, complexation, or aggregation has been very poorly described in the literature. It thus appears essential to study and characterize Pu(IV) colloids and in particular their surface charge properties which ensure their stability and their interactions with their environment. This pioneering project in the nuclear field aims to study and characterize colloidal Pu(IV) suspensions whose size, concentration and dispersion medium can be controlled by our approaches. It comprises: (i) the preparation of intrinsic Pu(IV) colloidal suspensions and the study of their chemical and sonochemical reactivity; (ii) the electrophoretic characterization of various colloidal suspensions and the study of their behavior under the influence of an electric field; (iii) the characterization of their multi-scale structural properties by small and large angle scattering (SAXS / WAXS) coupled with EXAFS / XANES measurements (MARS line, SOLEIL synchrotron).