: The use of cyclic olefin copolymer (COC) as a material for material extrusion 3D-printing is a novel approach in additive manufacturing. Its chemical inertness and high biocompatibility emerges the potential for chemical, biochemical, and life science applications while keeping the flexibility in design and manufacturing of 3D-printing. In this study, as functionalization, an incorporation of deviating weight ratios (28–20 wt%) of carbon black into the polymer matrix through a compounding process is shown. The resulting adjustable specific electrical resistivity (0.6–17 Ωm) of the conducive COC is specified with a high-precision measuring method. The material blends are used for the fabrication of several structures utilizing the electrical conductivity. With a panel of eight different solvents, the solvent and additionally the temperature stability are compared with those of a commercially available clear/conductive polylactic acid material set. In sum, the use of conductive and clear COC in material extrusion 3D-printing may be a future game changer for laboratory environments usage or small-scale experiments where highly specialized (hybrid) structures are needed.

Liquid–liquid slug flow in a microcapillary, with its improved heat and mass transfer properties and narrow residence time, plays a vital role in process intensification. Knowledge of the flow properties in microchannels along variables’ controllability (e.g., phase ratio, slug length along with classical variables, such as pressure, temperature, and flow velocity) during operation is crucial. This work aids in this by using magnetofluidics to manipulate these parameters. A ferrofluid with reproducible properties is produced and, together with another phase, stable slug flow is generated. Micro-gear pumps and syringe pumps, with their traditional mechanical components, result in parts degrading over time due to fatigue caused by pressure differentials and corrosive chemicals. The microflow is also disturbed by the invasive nature of these pumps. A considerably energy-efficient, non-invasive alternative, with reduced mechanical interfacing is suggested in this work. It uses magnetic gradients to manipulate two-phase flow, one of which is a magnetically active phase. Conveying concepts using permanent magnets in the immediate vicinity of the flow are investigated. To operate this pump continuously and to be able to regulate the phase ratio, an electromagnetic non-invasive valve is developed. Phase separation is also carried out with an existing decanter design, modified using electromagnetism to work without a selective membrane, usually necessary for phase separation at this scale. This pump is then compared with similar pumps developed in the past.