Bio-inspired construction of super-hydrophobic, eco-friendly multifunctional and bio-based cotton fabrics via impregnation method

Inspired by the super-wetting phenomena in nature, superhydrophobic, fluorine-free and bio-based cotton fabrics with multi-functionality have been prepared by a facile impregnation method. In this work, in situ prepared polydopamine (PDA) was utilized as a binder to adsorb the 8 % flame retardants consisting of ammonium polyphosphate (APP) and β-cyclodextrin (CD) onto the surface of cotton fabric, which was then modified with hydrophobic hexadecyltrimethoxysilane (HDTMS) to change the surface energy. The water contact angle and rolling angle of the cotton fabrics were 154° and 5°, demonstrating excellent self-cleaning capability and oil-water separation efficiency (99 % ± 1 %). Compared with pure cotton fabrics, the multifunctional cotton fabrics had exceptional flame-retardant properties that cannot be ignited. In addition, the cotton fabrics maintained superhydrophobic and flame retardant properties after 600 cm sandpaper friction tests, 7 times oxygen plasma etching-repairing tests, 20 times tape peeling tests, and knife cutting tests. And the multi-functionality mechanism of superhydrophobic cotton fabrics has been illustrated in detail. Consequently, a green and bionic modification presented in this paper via a novel route satisfies the demand for safety and functionality of cotton fabrics in the actual application.