Fluorine-free, superhydrophobic self-healing and UV-blocking cotton fabric for oil/water separation.

The discharge of oily wastewater not only pollutes waters but also deteriorates our living environment. Superhydrophobic cotton fabric is considered as an important remedy material for oily wastewater cleanup due to outstanding advantages including low cost, high porosity and switchable wettability. However, the existing superhydrophobic fabrics cannot exhibit durable superhydrophobicity during real-life applications due to poor interaction between the coatings and fabric substrates. To address this issue, one-step strategy is proposed to fabricate superhydrophobic cotton fabric by immersion in a octa-[2-(carboxyl methyl thio) ethyl]-polyhedral oligomeric silsesquioxane/cerium dioxide/polydimethylsiloxane (POSS/CeO₂/PDMS) coating. As expected, the finished cotton fabric exhibits robust superhydrophobic resistance to mechanical abrasion and chemical corrosions. Notably, the finished cotton fabric shows thermal self-healing superhydrophobicity even if undergone repetitive abrasion cycles and air plasma etching. It is proposed that the rising temperature accelerates the rotations of PDMS chains and the migrations of MAPOSS and CeO₂, contributing superhydrophobic self-healing of the damaged cotton fabric. Meanwhile, the superhydrophobic fabric displays high oil/water separation efficiency even in strong acid and alkali environments. Additionally, the POSS/CeO₂/PDMS coating improves mechanical, thermal and UV-blocking properties of the finished cotton fabric. This work will pave a way to exploitation and applications of novel multifunctional textiles.