Sizing melamine-formaldehyde microspheres using an electron microscope

Melamine-formaldehyde (MF) microspheres are widely used in complex plasma experiments because they are nearly monodisperse and are available in a wide variety of diameters. The manufacturer of these particles characterizes their mean diameter and standard deviation using a Coulter multisizer. However, measurements in complex plasma experiments, particularly of gas drag forces, indicate that the particles are smaller than their stated diameter. We have measured particle sizes using a scanning electron microscope and will compare these to the nominal diameter of $9.62\pm0.09~\mu\rm m$.