A facile route for the fabrication of surface-attached hydrogel thin films with well-controlled chemistry and tailored architecture on wide range of thickness from nanometers to micrometers is reported. The synthesis, which consists in crosslinking and grafting the preformed and enereactive polymer chains through thiol-ene click chemistry, has the main advantage of being wellcontrolled without addition of initiators. As thiol-ene click reaction can be selectively activated by UV-irradiation (in addition to thermal heating), micro-patterned hydrogel films are easily