| Spreading of Trisiloxanes on Thin Water Film: Moving Front Profile (2007) | |||||||||
Abstract | |||||||||
| The spreading of aqueous drops of surfactant on the surface of thin water film was recorded using an Olympus high speed video system with a speed of 100 frames per second. The surfactants used were trisiloxanes of polyethylene oxide chain length between 6 and 9 (EO6-EO9). The results showed that the spreading of trisiloxanes (EO6, EO7, EO8 and EO9) at concentration above their critical micelle concentration, CMC on a thin water surface of 320 microns film thickness involved two stages and was completed within few seconds. The images of the spreading of the surfactants show the development of a thickened front that spreads in the direction of uncontaminated interface. Upstream of the front, there exists a thinned region and the remnants of the drop that looks like a depressed cap. The initial stage of the spreading has a high power law exponent between 0.42 and 0.63; this is followed by a second stage characterised by a lower power law exponent between 0.28-0.35. The second stage was accompanied by the formation of dry spot at the centre of the Petri dish. | |||||||||
Publication details | |||||||||
| |||||||||