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Thin SiNwOxCyHz coatings were deposited from hexamethyldisilazane as a precursor in a microwave driven low pressure plasma enhanced chemical vapor deposition process, in order to investigate their suitability as silicon based separating layers in membranes for gas separation. Polydimethylsiloxane composite membranes were used as substrate, as they have a dense and defect free surface and by this provide a smooth surface to ensure a homogenous and defect free coating. To evaluate correlations between process parameters, coating properties and permeation/selectivity performance, the influence of different compositions of the feed gas (auxiliary gas and monomer) on the chemistry and structure of the coatings and subsequently on permeability were investigated. For this, auxiliary gas was varied (N2, none and Ar) and coatings/membranes were analysed regarding their structural properties with atomic force microscopy and cyclic voltammetry as well as their chemical properties with x-ray photoelectron spectroscopy. Correlations between those properties and the permeation properties were examined. The investigations reveal that coating and gas transport properties can be adjusted by changing the auxiliary gas type. Membrane selectivities could be produced that are above Knudsen selectivity, especially for the gas pairings CO2/N2 (up to 15), He/N2 (up to 9) and CO2/CH4 (up to 8) at 30 °C.

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Additive manufacturing of complex porous polymer geometries is a new field of advanced materials processing. Such new geometries can be used to fabricate porous polymer monoliths serving as a support for other material functions. Here, a novel fabrication technology to manufacture tailored 3D porous monoliths via additive manufacturing and templating is presented. The method is based on replicating a 3D‐printed mold with a polymer solution of polyvinylidenfluorid‐triethyl phosphate (PVDF‐TEP) and induce phase separation of the polymer solution subsequently. In a second step, the mold is removed without affecting the porous PVDF phase. As a result, porous monoliths with a templated 3D architecture are successfully fabricated. The manufacturing process is successfully applied to complex structures and can be applied to any conceivable geometry. Coating the porous 3D monoliths with another PVDF solution allows applying a skin layer yielding an asymmetric membrane monolith. As a showcase, a polydimethylsiloxane coating even leads to a smooth and dense layer of micrometer size. The methodology enables a new generation of complex porous polymer monoliths with tailored surface coatings. For the combination of poly(dimethylsiloxane) on a porous support, gas/liquid mass transfer is used in blood oxygenation with reduced diffusion limitation is within reach.