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Microstructured P(VDF-TrFE) Featuring Embedded Electrodes for Flexible Direction-Sensitive Strain Sensors and Micro-Harvesters Tomorrow’s Industry 4.0 environments raise a growing demand in self-sustained, flexible and low-cost sensors for versatile applications in process control as well as condition and energy monitoring. The printable ferroelectric copolymer poly(vinylidene-trifluoroethylene) (P(VDF-TrFE)) is a promising candidate as building block for such sensors.[1] After giving a short introduction to a common sensor architecture with its working principle, I will present a new concept for direction-sensitive and flexible strain sensors based on P(VDF-TrFE) and a single layer of interdigitated electrodes. Microstructured metal electrodes are formed on plastic substrates and embedded in the copolymer. Electric poling using the embedded electrodes (EE) allows the orientation of the ferroelectric domains primarily parallel to the P(VDF-TrFE)-substrate interface, thus having an increased piezoelectric coupling with respect to lateral strains present in the surface plane. A combination of (self-aligned) photolithography and electroforming was employed to produce 2 – 10 µm wide and up to 4 µm high electrodes that are fully covered by screen-printed P(VDF-TrFE). Alternatively, I will present an elegant structuring method based on microfluidic channels hot embossed into P(VDF-TrFE) which are filled with conductive ink to form high aspect ratio EE. Tensile and normal pressure tests with sensors having a footprint area of 1 cm² were performed and compared with FEM simulations. Furthermore, their energy harvesting potential was investigated for use in self-sustained sensor nodes. An outlook on related current and future works will complete my presentation. |