Preparation of self-healing superhydrophobic cotton fabric based on silica aerogel for self-cleaning and oil/water separation

Self-healing superhydrophobic coatings with excellent self-cleaning ability have received a lot of attention. A self-healing superhydrophobic cotton fabric was obtained by coating SiO2 aerogel and polydimethylsiloxane (PDMS) on a cotton fabric via the spraying process. Sol-gel reaction and ambient pressure drying (APD) were used to prepare hydrophobic SiO2 aerogel utilizing methyl trimethoxy silane (MTMS) as a precursor and water as a solvent in the presence of surfactant. Spraying a mixture of SiO2 aerogel and polydimethylsiloxane onto cotton fabric created the self-healing superhydrophobic cotton fabric. The surface morphology and chemical composition of superhydrophobic cotton fabrics were characterized respectively. The results showed that the treated cotton fabrics exhibited the superhydrophobic property with water contact angle (WCA) and water shedding angle (WSA) 161.1° ± 0.9° and 4° ± 0.5°, respectively, due to the simultaneous introduction of typical three-dimensional network porous structure caused by SiO2 aerogel and low surface tension PDMS layer on cotton fabrics. The treated cotton fabrics had not only excellent self-cleaning and anti-fouling properties, but also self-healing properties. The treated cotton fabrics showed excellent friction durability and laundering durability attributed to stable and firm PDMS adhesive layer. After 20 laundering cycles, 600 friction cycles or 8 cycles of etching-self-healing, the treated cotton fabrics were still superhydrophobic. The treated cotton fabric manifested desirable oil-water separation performance with a separation efficiency of 96.0%. These durable superhydrophobic fabrics with self-cleaning and liquid repellency may find various potential applications and display promising prospects.