Robust PFAS‐Free Superhydrophobicity Exhibited in Hierarchically Nanostructured Coatings on Textiles

Long chain per‐ and polyfluorinated chemical compounds, commonly referred to as PFAS, historically offered superior breathable and flexible water‐repellent textile finishes on clothing. Now notoriously deemed “forever chemicals” for their environmental persistence and ability to bioaccumulate, they can cause a range of human health impacts including cancer and reproductive harm, which has highlighted the need for less harmful but equally superhydrophobic coatings. Inspired by the microscopically bumpy water‐repellent surfaces of lotus leaves, this work introduces a PFAS‐free hierarchical nanocoating on and within textile substrates using a multistep synthetic approach, involving fabric pretreatment to facilitate a robust particle‐to‐substrate attachment of subsequently infiltrated silica nanoparticles (NPs), followed by surface functionalization of textile‐infiltrated NPs with long‐alkyl‐chain silanes to impart PFAS‐free water repellency. The system is subjected to rigorous wash testing and found consistent superhydrophobic performance after 65 wash cycles. Furthermore, the system can be adapted as a flexible platform technology for a variety of design opportunities by changing the substrate, NP composition, and surface chemistry to suit a variety of applications. Herein, a robust, flexible, and breathable interface between fabric and water that offers a next‐generation PFAS‐free water‐repellent textile coating solution is developed.