Monday July 30, 2007

This video was referenced last Tuesday when Jiangshui gave his paper presentation. It represents a drop of colored water on a thin triangular polymer film causing a phenomenon called "Capillary Origami." It was taken from "Capillary Origami:Spontaneous Wrapping of a Droplet With an Elastic Sheet" by Charlotte Py, Paul Reverdy, Lionel Doppler, Jose Bico, Benoit Roman, and Charles N. Baroud from Phy.Rev.Lett.98.156103 (issue 13 April 2007).I think it is really cool!


This morning, it is necessary to recalibrate the Tensiometer to water first, as it was used in another application over the weekend. We prepared a new 0.09% surfactant solution, then did three runs to determine its surface tension. The three readings were averaged, and the surface tension of the 0.09% solution is 46.5. Jiangshui now wants us to float films on water with surfactant added. We calculated how much of the 5% surfactant stock solution we needed to add to 200 ml of water to achieve the desired surfactant concentration. We will be counting the wrinkles on films floating on 0.03%, 0.08%, 0.12% and 3% surfactant solutions. Jiangshui's surface tension readings for the various surfactant concentrations are different from our readings.



Tomorrow we will prepare films, float them on the various surfactant concentrations, and count wrinkles!