  Face masks are used to intercept respiratory droplets to prevent spreading of
air-borne diseases. Designing face masks with better efficiency needs
microscopic understanding on how respiratory droplets move through a mask. Here
we study a simple model on the interception of droplets by a face mask. The
mask is treated as a polymeric network in an asymmetric confinement, while the
droplet is taken as a micrometer sized tracer colloidal particle, subject to
driving force that mimics the breathing. We study numerically, using the
Langevin dynamics, the tracer particle permeation through the polymeric
network. We show that the permeation is an activated process following an
Arrhenius dependence on temperature. The potential energy profile responsible
for the activation process increases with tracer size, tracer bead interaction,
network rigidity and decreases with the driving force and confinement length. A
deeper energy barrier led to better efficiency to intercept the tracer
particles of a given size in the presence of driving force at room temperature.
Our studies may help to design mask with better efficiency.
