Hence thick dense PDMAEMA brushes (s of 0.5 chains/nm 2 ; h of 30 nm) displayed highest swollen thicknesses compared to thinner or sparser brushes. In turn, sparser brushes (s of 0.1 chains/nm 2 ; h of 20 nm), but polymerised for longer times than the thinnest brushes (s of 0.5 chains/nm 2 ; h of 10 nm) displayed intermediate swollen thicknesses, in agreement with ellipsometry data. Overall, the total thicknesses measured by neutron reflectometry were higher than those measured by ellipsometry, in agreement with the greater sensitivity of this former technique to low density soft matter . But the total thickness of brush layers below 95 % solvent (Table ) were in good agreement with those measured by ellipsometry (Figure ). Beyond variations in swelling, depending on brush architecture, inspection of the thickness and water content of the different layers identified by our fits further revealed the impact of these architectures on their solution morphology (Table ). In all three PDMAEMA brushes, a thin layer (20-30 Å) close to the silicone oxide layer was found to be almost completely dehydrated, perhaps corresponding to the initiator layer together with a short region of non-hydrated brush. Subsequent adjacent layers were significantly more swollen, with water contents in the range of 50-65% water.