The elongational viscosities of aqueous solutions of polyethylene oxide (PEO) containing either sodium dodecyl sulfate (SDS) or sodium dodecyl benzyl sulfonate (SDBS) are measured by an opposing jet elongational rheometer. The elongational viscosities of these solutions are greatly enhanced by interactions between the polymer chain and surfactant micelles, and the behavior of the elongational viscosity-strain rate curves is complex, and strongly dependent on surfactant concentration. In the case of PEO-SDS solutions, abrupt rises in elongational viscosity are observed at critical values of strain rate, which vary with the SDS concentration. Data from these measurements are also employed to estimate elongational viscosities prevailing at the nozzle atomization stress in previous atomization experiments performed on PEO-SDS and PEO-SDBS solutions. Strong similarities are found between the variation of elongational viscosity and the variation of atomization droplet size with surfactant concentration. (c) 2006 Elsevier B.V. All rights reserved.