Experimental study of particle deposition on patterned microstructured surfaces in a chamber environment

Indoor respirable suspended particles may accumulate on textured surfaces such as sofa surfaces and office partitions via particle deposition. Previous studies mainly focus on particle deposition on non-patterned rough surfaces or patterned surfaces with texture scale larger than millimeters, and it is generally concluded that deposition rate increases due to the roughness. However, many indoor surfaces are patterned textures with scale in the order of 100 μm and there is a lack of study of particle deposition behavior in this regime. This study investigates the effect of patterned microstructured surfaces on particle deposition in a turbulent chamber. Different shapes (triangular, rectangular, semi-circular convex and semi-circular concave ribbed structures) and pitch-to-height ratios (i.e. ratio of spacing to height) of patterned structures were studied. Particle sizes ranging from 0.3 μm to 5 μm in diameter were tested. It is found that for submicron particles, deposition velocity was increased by the patterned microstructures, and triangular-ribbed surfaces achieved the highest deposition velocity, which was 10 times higher than that on a non-patterned surface. For micron particles, it is found that deposition velocity was lower than that of a non-patterned surface. Our results show that particle deposition is not always enhanced by roughness and it is possible to be reduced by a suitable length scale of patterned structures.