Preparation of Polyurethane/MXene Composite for Strain Sensor Applications

Flexible and multifunctional strain sensors have attracted a great deal of attention due to their diverse applications in health monitoring devices, smart robotics and wearable electronic devices. Typically, flexible strain sensors consist of a sensitive conductive element and a stretchable, flexible platform. Our study delineates the preparation and characterization methodology for a strain sensor fabricated using a straightforward spin-coating technique. The platform of the sensor is a flexible and biocompatible polyurethane (PU) substrate, onto which a conductive layer of Ti
3
C
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Tz MXene was applied. A crosslinked polyurethane, comprising a 50/50 ratio of soft and hard segments, was synthesized via a two-step polyaddition process in solution, endowing the polymer with optimal mechanical properties. The MXene was prepared through a conventional MILD etching method, followed by dispersion onto the platform's surface. Sensor characterization was accomplished through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and electrical resistivity measurements under varying loads. The sensor's performance was evaluated by measuring its relative resistance during cyclic shape changes and weight loading. Electrical measurements have shown us that this type of PU-MXene composite-based device can be used as a strain sensor.