PFAS-free waterproof breathable membrane technologies

Waterproof and breathable membranes (WBMs) enable air and moisture vapor transfer while blocking solid particles and water penetration, and are widely used in medical healthcare, outdoor apparel, and environmental protection. However, most commercial WBMs rely on per- and polyfluoroalkyl substances (PFAS), raising environmental and health concerns and driving the development of PFAS-free alternatives. Despite rapid progress, a comprehensive understanding of how fabrication strategies govern membrane structure, performance, and scalability remains lacking. This review systematically compares PFAS-free WBMs fabricated by phase inversion, film stretching, melt extrusion, sacrificial templating, and electrospinning, emphasizing the structure-property-performance relationships and trade-offs among water resistance, vapor permeability, mechanical strength, thermal stability, durability, and sustainability. The advantages, limitations, and industrial prospects of each approach are critically evaluated, thereby providing a practical framework for designing the next generation of sustainable PFAS-free WBMs.