MONOLAYER SPREADING OF POLYDIMETHYLSILOXANE OIL ON SURFACTANT SOLUTIONS

The radial spreading rate of polydimethylsiloxane oil monolayers on va rious surfactant solutions is measured by observing Teflon tracer part icles with a video microscope. We find that a simple model, based sole ly on Marangoni driven surface tension gradients, accurately predicts the power-law behavior observed for these expanding monolayers. In add ition, we document observations of so-called pseudopartial wetting, an d discuss its connection to more classical wetting theories.