Facile fabrication of superhydrophobic and flame-retardant coatings on cotton fabrics via layer-by-layer assembly

The hydrophilicity and intrinsic inflammability of pristine cotton fabrics severely restrict their applications. To overcome these disadvantages, a superhydrophobic and flame-retardant (SFR) coating with micro-nano hierarchical structures was fabricated onto cotton fabric by sequentially depositing branched poly(ethylenimine), ammonium polyphosphate (APP) and fluorinated silica@polydimethylsiloxane composite (F-SiO2@PDMS) via facile dip-coating and layer-by-layer assembly methods. The SFR cotton fabric not only exhibited superhydrophobicity with contact angle of 158 degrees, but also possessed excellent self-cleaning and antifouling properties as well as superior thermal stability and acid/alkali resistance of superhydrophobicity. Interestingly, the SFR coating with hydrophilic property led by plasma etching could gradually recover to superhydrophobicity after heating at 100 degrees C for 2 h. Moreover, when suffering to fire, the SFR coating could generate intumescent char layers rapidly and extinguish the fire due to the synergistic effect of F-SiO2@PDMS and APP, providing outstanding flame-retardant properties to cotton fabric.