Electromagnetic interference shielding, hydrophobic, and multifunctional flexible sensor based on optimized design of Gr/Fe NW bi-ordered porous structure

This study develops a flexible strain sensor with electromagnetic interference (EMI) shielding, hydrophobicity, and acid/alkali resistance by integrating a bi-ordered porous structure with a micro-raised surface. The structure, mimicking lotus leaves, is fabricated using magnetic field-assisted freezing orientation and laser ablation on graphene (Gr)/Fe nanowire (NW)-infused aerogel and polydimethylsiloxane. The sensor, with a Gr to Fe NW ratio of 9:1, shows a high gauge factor of 85.19 in the 0–30% tensile strain. These values are 304%, 430%, 702%, and 1226% of the samples with Gr to Fe NWs ratios of 7:1, 5:1, 3:1, and 1:1, respectively. It achieves an EMI shielding efficiency (SE) of 20.02 dB and a specific SE of 807.48 dB cm 2 /g in the 8.2–12.4 GHz range, 150% higher than isotropic samples. The sensor exhibits a contact angle of 155.76°, maintaining hydrophobic stability under stretching and showing excellent resistance to acid and alkali. Additionally, the sensor can be integrated into wearable devices like gloves for gesture recognition, machine hand manipulation, and controlling neon bulbs, demonstrating potential for applications in field robotics and human-robot interaction.