Particle size infl uences many properties of particulate materials and is
a valuable indicator of quality and performance. This is true for powders,
suspensions, emulsions, and aerosols. The size and shape of powders infl uences
fl ow and compaction properties. Larger, more spherical particles will typically fl ow
more easily than smaller or high aspect ratio particles. Smaller particles dissolve
more quickly and lead to higher suspension viscosities than larger ones. Smaller
droplet sizes and higher surface charge (zeta potential) will typically improve
suspension and emulsion stability. Powder or droplets in the range of 2-5μm
aerosolize better and will penetrate into lungs deeper than larger sizes. For these
and many other reasons it is important to measure and control the particle size
distribution of many products.