The first article in this series ended with a discussion on using fogging to assist particle control, and the importance of proper droplet size. Smaller, light particles tend to be more effective because they are then similar or smaller in size than the particles being removed from the air.

Just like smaller water droplets do a better job of collecting smaller particles, the same can be said for fibers in a cleaning cloth. The smaller the fiber size, the more effective a cloth is at capturing and removing small particles. Cotton and nylon, the two materials most prevalent in standard cleaning cloths, have fiber diameters that generally range from 10 to 50 microns1. In contrast, lower grade microfiber cloths have fibers with diameters of 1 to 5 microns; with the best ones having fiber sizes in the 0.3 micron range. The small fiber size means that many more strands are present per square inch. The small fibers actually use the van der Waals molecular electrical properties to their advantage (see part 1 of this series from the September issue for more on this!). They are so small that they can interact with the tiny particles and switch the attractive force of the particle from the surface to the fiber. This impressive (or confusing) sounding science explains why microfiber cloths are so efficient at removing small particles.