Multifunctional Superamphiphobic Cotton Fabrics with Highly Efficient Flame Retardancy, Self-Cleaning, and Electromagnetic Interference Shielding.

Here, a facile method is reported to prepare multifunctional cotton fabrics with high flame retardancy, high electrical conductivity, superamphiphobicity, and high electromagnetic shielding. The cotton fabric surface was first modified with phytic acid (PA), which promoted dehydration and carbonization of cellulose to increase flame retardancy in the process of pyrolysis. Tannic acid (TA) and 3-aminopropyltriethoxysilane (APTES) coating with nanospheres as interlayers created hierarchical roughness that facilitated the construction of superamphiphobic surfaces and provided adhesion sites for silver nanoparticles. In addition, the TA-APTES coating improved flame retardancy because the APTES-containing silicon could form silicon carbon layers to isolate heat and oxygen. Subsequently, the surface energy of the composite cotton fabric was reduced by fluorine-containing molecules. The prepared composite cotton fabric exhibited excellent superamphiphobicity with contact angles of 160.3 and 152° for water and olive oil, respectively. The conductivity and EMI shielding efficiency of the prepared composite cotton fabric reached 629.93 S/cm and 76 dB, respectively. Importantly, the composite cotton fabric maintained a relatively stable EMI shielding efficiency even after cyclic bending and abrasion tests. Moreover, the composite cotton fabric possessed a high limiting oxygen index (LOI) of 45.3% and self-extinguishing properties with the peak heat release rate (PHHR) and total heat release (THR) reduced by 73 and 67%, respectively, than the pure cotton fabric, indicating the outstanding flame retardancy.