Swelling Dynamics of Disk-Shaped Nonwoven Membranes: A Theoretical and Experimental Study

Understanding the swelling behavior of porous membranes in the presence of wetting liquids is essential for optimizing performance in applications ranging from industrial fabrics to healthcare textiles. Here, a combined experimental and theoretical approach is used to explore water imbibition and swelling and to quantify it in terms of two physical parameters: the equilibrium swelling coefficient (α_eq) and the transport coefficient (D). Unlike traditional approaches that focus solely on absorption measurements, the present method directly links the theory of swelling dynamics with experimental data. A diverse set of ten different materials, including paper, dry wipes, healthcare-grade nonwovens, industrial fabrics, and mercerized cotton, was evaluated using high-resolution imaging to track disk swelling. A nonlinear least-squares (NLS) method was employed to extract the physical parameter values (α_eq and D) from the experimental data. The results reveal not only excellent agreement between the theory and experiment but also provide a novel direct, quantitative comparison of diverse water-imbibing and swelling materials, with dry wipes exhibiting the highest swelling and mercerized cotton the lowest. The findings are particularly relevant for industries that rely on controlled fluid uptake, such as hygiene products, medical dressings, and absorbent substrates.