Thermoresponsive Viscoelasticity of Sodium 1-Oxo-1-[4-(tridecafluorohexyl)phenyl]-2-hexanesulfonate Aqueous Solutions

The thermal viscosity behavior or temperature-dependent viscosity of an aqueous solution of sodium 1-oxo-1-[4-(tridecafluorohexyl)phenyl]-2-hexanesulfonate (FC6-HC4), a fluoro-hybrid type surfactant, which has a fluorocarbon chain and a hydrocarbon chain in a molecule, was examined. The FC6-HC4 solution showed viscoelastic behavior at concentrations around 10 wt %. Further study on the temperature dependence of the viscosity of a 10 wt % solution revealed that the viscosity increased about 10 2 times, showing a maximum as temperature rose from 6 to 36 °C, and then decreased about 10 - 4 times with further rising at in temperatures up to 64 °C. Moreover, tan δ, a parameter for viscoelasticity, exhibited a minimum at 36 °C. The phenomenon found in this work was reversible with respect to temperature change. In other words, an aqueous solution of FC6-HC4 was found to show thermoresponsive viscoelastic behavior.