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This study presents the fabrication and characterization of novel surface-type capacitive humidity sensors using vanadyl phthalocyanine (VOPc) as the active material. The devices, which comprise three different thicknesses, have been fabricated using the thermal evaporation technique. A thin film of VOPc is deposited on thoroughly cleaned glass substrates with pre-patterned Ag electrodes. The capacitive effect of the samples under humidity has been investigated. Comparison of the samples with different thicknesses shows that the thinnest device seems more sensitive towards humidity. The humidity dependent capacitance properties of the sensor make it beneficial for use in commercial hygrometers.

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To address the strength–toughness dilemma, various techniques for the preparation of ceramic–metal composites have been proposed. Utilizing stereolithographic additive manufacturing and centrifugal infiltration, a method for the preparation of bio‐inspired ceramic–metal composites is proposed. The proposed method offers flexibility in the design of individual phases of ceramic–metal composites architecturally, with the benefits of scalability and individual phase dimensional control. The versatility of this approach is demonstrated by fabricating silica–aluminum composites with structures inspired by mineralized layers in bivalve mollusk shells, including both 2D prismatic and 3D interpenetrating composites. For composites in compression, the measured specific strength is as high as 169% than that of the base metal (monolithic 6061 aluminum alloy). The highest crack growth toughness of 12.89 MPa m1/2 is recorded. The crack growth sequence shows crack deflection at ceramic–metal interfaces. Based on the tomographic structural analysis of the ceramic parts, the porosity of the green and sintered parts are 9% and 15%, respectively. It is believed that the strength and fracture toughness of these ceramic–metal composites could be further improved if the mechanical properties of the ceramic components can be improved by reducing porosity and structural defects during printing and sintering steps.

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