Bio-based materials exhibit strong potential for filtration applications as they reduce dependency on fossil resources and provide high active surface area with water responsive behaviour, containing a lot of untapped potential. Water interactions are crucial for filter and membrane materials, affecting their swelling, transport properties, stability, as well as the filtration and separation performance. Moreover, interfacial water dictates the materials’ interactions with aqueous solutes and gas molecules while also providing resistance towards fouling. Experimental techniques covering water conveying mechanisms in macroscopic scale, such as morphology and porosity analysis as well as flux and retention tests are well-established.

However, analytical tools for probing interfacial and molecular-level water sorption at complex heterogeneous interfaces are sparser and often rely on simulations. Exploiting our in-house analytical capabilities together with our expertise in surface science allows us to investigate the water responsiveness of fibre-based and polymeric materials from molecular to macroscopic scales. Combining 2D ultra-thin films with surface sensitive acoustic sensing via Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) enables detection of water and vapour uptake at material interfaces with nanogram precision.

Coupled with Dynamic Vapour Sorption (DVS) and Karl-Fischer titration suitable for 3D materials structures, our analytical toolbox paves way for examining water interactions across a span from individual fibres, polymer surfaces, and complex bulk materials architectures, including films, porous objects, and non-wovens, towards real-life filter and membrane constructs.