RESUMO
The limited control over the printing process in commercial powder bed 3D printers hinders the exploration of novel materials and applications. In this study, a custom binder-jetting 3D printer was developed. The resulting fine-grained control over the printing process enables features such as voxel-based control over the printed ink volume, adaptive layer thickness, and selective multi-pass printing. A protocol was developed to optimize the 3D printing process for new build materials and binders, in which resolution tests were used as a guideline for improving the dimensional accuracy. As a demonstration of the voxel-based control over the printing process, a functionally graded object was printed.
RESUMO
Encoded fluorescent particles are fabricated through the selective uptake of dyes in photopatterned metal-organic framework single crystals. The concept is based on spatially controlled photochemical cleavage of pore-blocking pendant groups. Because of the crystalline and porous nature of the host, this approach enables guest uptake that is tunable and can be triggered though controlled irradiation.
RESUMO
We present a highly sensitive gas detection approach for the infamous 'nerve agent' group of alkyl phosphonate compounds. Signal transduction is achieved by monitoring the work function shift of metal-organic framework UiO-66-NH2 coated electrodes upon exposure to ppb-level concentrations of a target simulant. Using the Kelvin probe technique, we demonstrate the potential of electrically insulating MOFs for integration in field effect devices such as ChemFETs: a three orders of magnitude improvement over previous work function-based detection of nerve agent simulants. Moreover, the signal is fully reversible both in dry and humid conditions, down to low ppb concentrations. Comprehensive investigation of the interactions that lead towards this high sensitivity points towards a series of confined interactions between the analyte and the pore interior of UiO-66-NH2.
