2. Technical description of the innovation

The first step in the manufacturing process is to form a PDMS film (Dow Corning Sylgard 184 Kit) on a glass substrate. Thin films, up to 100 μm thick, are prepared by centrifugal coating, while thicker films are made by casting. The polymer/crosslinking agent ratio is 10:1. The film is crosslinked at 100°C for 30 min on a hot plate. The second layer is then formed on top of the first film, using PDMS containing silicon oil (Rhodorsil, 47 V 350). The oil volume fraction, x = V _oil /(V _oil + V _PDMS ), ranges from x = 0 to x = 0.6. Higher values of x suppress the formation of a continuous cross-linked elastomer network due to excessive dilution of PDMS in the oil. The sample is again passed to the hot plate and the second oil-containing layer is crosslinked...