Fabrication of fluorine-free superhydrophobic cotton fabric using fumed silica and diblock copolymer via mist modification

Immobilizing inorganic particles to improve the roughness or coating with fluorinated agents and polysiloxanes to reduce surface energy is the most popular approach for constructing superhydrophobic cotton fabrics. However, the poor durability, health and environmental concerns, and other serious drawbacks limit the application of superhydrophobic cotton fabrics. In the present work, we describe a simple and facile fabrication strategy to construct robust fluorine-free superhydrophobic surfaces of cotton fabric via a mist technique. The modified cotton fabrics were first immobilized by fumed silica (SiO2) particles to improve the roughness and then covered with a diblock copolymer of poly[(methyl methacrylate)-b-(lauryl methacrylate)] (PMMA-b-PLMA), which was synthesized by RAFT polymerization, to reduce the fabric’s surface energy. The mist technology used ensures that the PMMA-b-PLMA covers the SiO2 particles on the surface of the fabric with a thin coating. Therefore, the SiO2 particles were stably immobilized on the fabric surface without reducing the roughness. As a result, the water contact angle (WCA) values of the prepared cotton fabrics reached reached 156.7°±0.5°. Moreover, even after 1600 abrasion cycles or 80 laundering cycles, the WCA values of the fabric samples were still higher than 150.1°±0.5°. The stable superhydrophobic cotton fabric surfaces are useful for self-cleaning, oil-water separation, and other potential areas.