Combination of ionic copolymer micelles with oppositely charged polyelectrolytes leads to the formation of interpolyelectrolyte complexes (IPECs). The aggregate has an onion- like structure, consisting of three parts: a hydrophobic core, an IPEC shell and a corona. The sizes of all parts can be tuned and controlled independently. Domains of different polarity make IPECs extremely interesting delivery systems, which can be used e.g. in drug-delivery.The aim of the proposed experiment is, first, to investigate in thorough detail the structural changes (swelling/growth and shape) of copolymer micelles induced by the solubilisation process within aqueous media and to link the solubilisation capacity to the core design and hydrophobicity of the produced systems. Aimed solubilisates are oils, deuterated oils and a cancer drug. As an exploratory study also some of the IPECs shall be studied.