Superhydrophobic self-extinguishing cotton fabrics for electromagnetic interference shielding and human motion detection

Multifunctional intelligent fire-safe cotton fabric promises next-generation fire-fighting uniform and sensor applications. However, cotton fabrics' hygroscopicity and intrinsic flammability significantly impede their potential applications in industries. Herein, we report a superhydrophobic fireproof cotton fabric (PEI-APP-PEI-MXene) generated via sequential layer-by-layer deposition of polyethyleneimine (PEI), ammonium polyphosphate (APP), and titanium carbide (MXene), followed by hydrophobic treatment with silicone elastomer. Compared to untreated cotton, the treated cotton fabric with 10 polymolecular layers exhibits ∼43% and ∼42% reductions in the peak heat release rate and total heat release, respectively, a desired UL-94 V-0 rating, and a high limiting oxygen index (LOI) value of 39.5 vol.%. In addition to that, the treated fabrics displayed improved electromagnetic interference (EMI) shielding and motion-sensing abilities. The presented work provides a facile and effective surface modification approach to generate multifunctional cotton fabrics with promising practical applications.