With the advancement of material science and electronic technology, wearable devices have been integrated into daily lives, no longer just a stirring idea in science fiction. In the future, robust multifunctionalized wearable devices with low cost and long-term service life are urgently required. However, preparing multifunctional wearable devices robust enough to resist harsh conditions using a commercially available raw material through a simple process still remains challenging. In this work, reprocessable polyurea (HUBTPU) with a hard segment of hindered urea bonds (HUBs) and a soft segment of polyether is synthesized via a facile one-pot method. The robust dual functional wearable devices were obtained by simply spray-coating silver nanowires (AgNWs) on HUBTPU elastomer substrates. Due to the dynamic combination and decomposition of the HUBs and hydrogen bonds at 130 °C, the robust elastomer demonstrates favorable adhesion to various substrates. Especially, the partially embedded AgNW structure is also achieved by using ethanol as a spray solvent. The adhesion of HUBTPU substrates and embedded structure leads to stronger interfacial adhesion and stability compared to non-adhesive substrates. The as-obtained HUBTPU electrodes are able to be heated to 115 °C by applying a low voltage and sensing the strain deformation caused by human movement, which means that the electrodes are endowed with both electrical heating capability and strain sensing functionality. Therefore, this strategy reveals a potential way to prepare multifunctional wearable devices using other conductive particles and adhesive functional polymer substrates.
Keywords: electrical heating; hindered urea bonds; reprocessable polyurea; strain sensing; wearable device.