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Tailored and Highly Stretchable Sensor Prepared by Crosslinking an Enhanced 3D Printed UV‐Curable Sacrificial Mold

Taking advantage of unlimited geometry design, 3D printed sacrificial mold cast with highly conductive polymer composites is used to prepare a sensor with designed structures. However, the disposal of the mold in a mild condition while the refined structures can be maintained is still a challenge. Herein, a bifunctional monomer hydrolyzable hindered urea acrylate is synthesized to create a cross‐linked polymer network, preventing the dissolution of printed parts in the uncured resin. 3D printed scaffolds can be hydrolyzed in hot water, which provides an attractive option for sacrificial molds. Also, a porous flexible strain sensor (PFSS) is fabricated by casting polyurethane/carbon nanotubes composites into the sacrificial molds, which demonstrates a high stretchability (≈510%) and an excellent recoverability. Meantime, the pressure sensitivity (0.111 kPa−1) and a long‐term electrical resistance of PFSS is characterized. The resistance response signal remains nearly unchanged after 100 compressive loading cycles at a large strain of 60%. Benefiting from the design freedom of 3D printing, a practical application of the PFSS with a complex and customized structure to monitor human motion is demonstrated. These results prove that the sacrificial molding process has great potential for user‐specific stretchable wearable devices.