Silver nanowire penetration through screen filter

Abstract

Understanding the filtration characteristics of fibrous particles is important since those particles have caused health and environmental concerns. Due to the straight morphology of metal nanowires, unlike carbon nanotube (CNT) particles nanowires can be considered as appropriate test material to evaluate existing filtration theory for cylindrical particles. We measured the penetration of silver nanowires in the size range of dm = 200 to 400 nm through screen mesh filter. By using Li et al. (2012)'s theory, we determined the orientation status of silver nanowires inside differential mobility analyzer (DMA) and calculated the dynamic shape factor of nanowires. Theoretical penetration was obtained by using single fiber theory with modified interception parameter including orientation angle between a filter wire and a particle. The orientation angle obtained by fitting experimental data into single fiber theory for the 1 layer of screen mesh filter is found to be close to 40° indicating random orientation of nanowires near filter. However, in the experiments with multi-layers of screen mesh, any tendency related to the orientation angle was not found. We performed numerical simulations for the filtration processes such as impaction, diffusion, interception, and interception of diffusing particles by introducing modified slip correction factor. Overall, when interception of diffusing particles is considered in addition to diffusion and interception, numerically simulation results and theoretical prediction agree better with experimental data regarding the penetration of silver nanowires through the 1 layer of screen mesh filter. © American Association for Aerosol Research.