X－ray reflectivity investigation of the foam bilayer film formed by hexaethylene glycol dodecyl ether

When the thickness of soap foam film varies in adefinite region, color changes of a soap bubble will be observed due to the interference of light. Black soap films are the final stages of thinning of soap films due to the drainage of water in the absence of evaporation and are generally formed from solutions of an ionic surfactant in the presence of salt. After a bubble is formed, in the beginning the soap film is relatively thick and it appearswhite; then the film thins gradually and finally …

X-ray reflectivity investigation of the foam bilayer film formed by hexaethylene glycol dodecyl ether

Structural parameters for the free-standing foam film of hexaethylene glycol monododecyl ether (C12E6) have been measured by using X-ray reflectometry. The re-sults indicate that a five-laminae model corresponds to this inverted bilayer and divides it into five regions. The thick-nesses of the aliphatic chain regions, the polar head-group regions, and the central aqueous core are 0.90, 1.35 and 1.31 nm, respectively; and their corresponding electron densities are 2.4 10-3, 2.6 10-3 and 2.310-3 electron/nm3, respec-tively; the interfacial roughness between adjacent regions is 0.34 nm. The central core of this foam film does not contain free water, its thickness decreased 0.40 nm under the irra-diation of infrared rays due to the loss of structural water.