Enhanced Capture of Aerosol Particles on Resonator-Based PM Mass Sensors Using Staggered Arrays of Micro-Pillars

This work presents the effect of addition of micro-pillars with different array configurations on the particle collection efficiency (CE) of resonators for gravimetric airborne particulate matter (PM) sensors. Inline and radially staggered arrays of micro-pillars with rectangular and circular cross sections were 3D-printed on a surface of fused silica glass using 2-photon stereolithography and the particle collection efficiency of these pillar-covered surfaces due to impaction was evaluated. The experimental results show that in some cases the CE is highly dependent on the angle of incidence and array configuration of the pillars. The CE of inline array of rectangular micro-pillars (60%) was similar to the CE of the bare surface with no pillar. However, the radially staggered arrangement of the same pillar size and geometry improved CE by 25% on average. The presented result shows the strong significance of the incident angle, array configuration, and pillar shape on particle capture behavior of the pillared-enhanced impaction surfaces. The results pave the way for highly sensitive real-time gravimetric PM mass sensors. [2020-0124]