Controllable synthesis and functionalization of SiO2 nanoflowers for fluorine-free superhydrophobic fabric-based oil/water mixture and emulsion separation

Abstract

The fabrication of superhydrophobic fabrics has gained significant interest due to their potential in applications like oil/water separation, yet conventional methods often involve fluorine-based materials, raising environmental concerns. Herein, we introduce a fluorine-free strategy for creating superhydrophobic fabrics by coating nano flower-like SiO₂ (NFS). These nanostructured SiO₂ synthesized via a facile and controllable hydrothermal method were functionalized with thiol groups (–SH) to enhance bonding using (3-mercaptopropyl)trimethoxysilane (MPTMS). The MPTMS modified NFS (MNFS) were applied to cotton fabrics pretreated with cross-linking agents and low-surface tension polymers, followed by UV curing to ensure robust adhesion. The resulting fabric demonstrated superior superhydrophobicity with a water contact angle of 168.6°, along with an excellent separation efficiency of 96.2% for water-in-oil (dichloromethane) emulsions and a significant flux rate of 35.09 × 10³ L m⁻² h⁻¹ for oil/water mixtures. Moreover, the fabric exhibited notable resistance to UV radiation, chemical exposure, and mechanical washing. This fluorine-free approach to superhydrophobic fabric design provides an environmentally responsible alternative for water treatment and industrial oil/water separation, with potential applications extending to sustainable environmental and industrial solutions.