The micropatteming of a surface modified polyurethane is proposed in this paper. In previous work, we described the development and characterisation of a series segmented polyurethanes. These polymers are irradiated with UV excimer lasers (ArF: lambda = 193 nm and KrF: lambda = 248 nm excimer laser). After determining the ablation properties of the synthesised polymers, one of these polyurethanes is selected and treated with a new developed method to graft hydrophilic polyacrylamide onto the hydrophobic surface. This modification is observed with spectral reflectance IR, static contact angle measurements, scanning electron and atomic force microscopy. This substrate is treated with an UV excimer laser (ArF, 193 nm) for micropatteming. The grafted polyacrylamide layer shows no interference with the patterning procedure: the polyurethane keeps its good ablation properties in terms of no debris formation and cavities with high dimensional quality (sharp edges and low surface roughness), measured with atomic force microscopy. Also the modification with PEO-macromonomers is executed (AFM, attenuated total reflectance IR and scanning electron microscopy) and shows promising results for a successful usage towards the patterning procedure. This combination of surface modification and micropatterning with UV excimer lasers can be of value in the development of new biosensors. (C) 2002 Elsevier Science B.V. All rights reserved.