Wearable, skin-like sensor devices embedded in stretchable substrate materials like thermoplastic polyurethane (TPU) have paved the way to manifold applications in the field of personalized health monitoring. They are accompanied by exceptional features such as a high durability, stretchability and a lightweight character. This opens up the detection of diverse physiological parameters and biomarkers.

It results from the improvement of various additive techniques which overcome technological obstacles of established photolithographic approaches with respect to the overall process costs, the necessity of time-consuming fabrication steps within a cleanroom environment and, at the same time, enable a sustainable fabrication of flexible sensors and relating electronic components. To this end, the cutting-edge electrohydrodynamic (EHD) printing technology [1,2] for a precise patterning of microscaled wearable sensor structures is investigated in-depth within this project by finite-element-based simulations (cf. Figure 1).

This extremely efficient printing approach is based on an electrohydrodynamically induced fluid flow through a capillary nozzle initiated by an appropriate electric field in the kV-range applied between the nozzle tip and the substrate. Moreover, this procedure leads the formation of the so-called "Taylor-Cone" and a filigree conejet with a diameter that is up to two orders of magnitude smaller than the inner nozzle diameter (cf. Figure 2 (a)). By utilizing a dielectric, conductive or biological medium, an accurate patterning of functional sensor structures is permitted. For a validation of the simulation results as well as for the fabrication of first demonstrators (Figure 2 (b) & (c)), an EHD printing system on laboratory scale is additionally developed.