Efficient air filtering materials are crucial for environmental health and industrial safety. Nanostructured fibrous materials offer improved capture of airborne particles and optimize filtration efficiency due to their fine dimensions and large surface area-to-volume ratios. On the other hand, these materials often suffer from an increase in pressure drop across the filtering layer and low mechanical stability. Thus, composite morphologies are being researched to optimize the filtration performance. This study aimed to fabricate and characterize multilayer nano- and micro fibrous materials. Moreover, the study employed commercially available biobased polymers to address the issue of non-renewable resources.

Layered filtering materials were fabricated using a fiber printing process (3Df-01C, Bious Labs, Lithuania) from commercially available biobased polymers, including poly (butylene succinate) (NaturePlast SAS) and polyamide (EMS-Chemie AG). This apparatus integrates melt and solution electrospinning to create micro and nanofibrous layers, respectively. Filtration efficiency was evaluated by challenging the matrices with aerosolized NaCl and DEHS solutions using a filter material setup developed at KTU and measuring particle concentrations with an electric low-pressure impactor (ELPI+, Dekati Ltd.).

A range of nano/microfibrous filtering materials was obtained (Figure 1) through various layering schemes, allowing controlling filtration efficiency between 70 to 99%. The optimum layering patterns were selected based on the lowest filter quality factor.