Measurement of dewetting processes using environmental scanning electron microscopy

Droplet scale dependence of the contact line motion

Abstract

The understanding of microfluidic phenomena is one of the key issues for the development of the printed electronics technology. For example, the contact line pinning of droplets is a critical phenomenon which often prevents accurate, reliable micron-scale pattering of circuits on polymer substrates. Here, we report the observation of water droplets using an environmental scanning electron microscope (ESEM), focusing on the dewetting process, i.e., the contact line motion of evaporating droplets with diame ters less than 100 μm on a parylene-C surface. The ESEM observation reveals how the droplet scale impacts on the pinning of contact lines. The results for the wetting (condensation) process is also presented.