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Technology

The inventors developed a bi-/multi-layer PDMS (silicone) soft-lithography stamp. One layer is either chemically modified or doped with fluorescent particles or dye, so that functional groups, molecules or particles provide different optical or electrical properties. This stamp is used for microcontact printing. The stamp is produced by an additive manufacturing fashion, casting layers on top of each other. Each layer is entirely or partially crosslinked by the time the next layer is cast. The stamp material is cast into a centrifuge to create a seamless cylindrical stamp. To create the mold on the inner surface of the centrifuge, two layers of photoresistive polymer are applied to it: a fully-covering coat for creating a planar surface and a laser-structured layer that provides the pattern. The technique of varying optical properties allows for new methods of continuous inspection and control of the printing process. Other functional properties can be introduced to the layers with regard to applications in advanced metrology and contact control; such layers could provide for various sensing, actuating or thermal control purposes.