Modeling performance of thin fibrous coatings with orthogonally layered nanofibers for improved aerosol filtration

Advances in nanofiber fabrication techniques (e.g., electrospinning) have come to allow control over fiber distribution and orientation such that an ordered coating with fibers arranged in layers orthogonal to one another can potentially be produced. Such coatings can serve as a nano-sieve that can be designed and placed on the downstream side of a conventional nonwoven fibrous filter to enhance its performance (collection efficiency for a given pressure drop). This paper presents a thorough analysis of the performance characteristics of these thin coatings to guide the fabrication process in terms of the coatingsʹ microstructural properties. In particular, we have found a correlation such that, for coatings composed of a given fiber size, there exists a corresponding particle size for which a coatingʹs performance becomes independent of variations in fiber-to-fiber spacing (i.e., coatingʹs non-homogeneity). We have also found that a coatingʹs performance improves when its mass is distributed across more than one pair of orthogonal layers.