We are investigating innovative hybrid organic/inorganic multilayered films comprising alternated layers of cellulose nanocrystals (CNCs) and Gibbsite platelets (GW). CNCs are rod like biosourced nanoparticles exhibiting outstanding physical properties that appear as perfect building blocks for the preparation of green or hybrid nanocomposites. The architecture of (CNC/GW) multilayered films was shown to be highly tunable by varying the drying protocol and the salt content. We propose here to investigate by neutron refelctivity the swelling properties of (GW/CNC) multilayers. It indeed appears crucial to check if phenomena like swelling, thickness increase, rearrangement of the nanoparticles, or desorption occur in order to understand the final dry state.