Interfacial Properties of Aqueous Nonionic Fluorocarbon Surfactant Solutions |
| |
Authors: | Suraj Chandra Sharma Lok Kumar Shrestha |
| |
Institution: | Graduate School of Environment and Information Sciences, Yokohama National University , Yokohama, Japan |
| |
Abstract: | The equilibrium, dynamic surface tensions, and surface dilatational elasticity of aqueous solutions of nonionic fluorocarbon surfactant are reported. The critical micellar concentration, CMC (0.023 mM) and equilibrium surface tension (24.6 m N . m?1) at CMC were measured by Wilhelmy plate method for aqueous solution of C8F17SO2N(C3H7)(C2H4O)nH (n=20), abbreviated as EF122A. The surface tension decay is slower for C8F17SO2N(C3H7)(C2H4O)nH (n=10) system, abbreviated as EF122B compared to the EF122A system over short time region, which indicates the slow transport of the surfactant molecules to the surface. The relaxation time for surface tension decay is estimated by fitting a series of exponentials to the dynamic surface tension data and it decreases with temperature for EF122A. Slow exchange of monomers between bulk and interface is reflected in the high elasticity value of the air‐liquid interface for EF122B compared with EF122A within measured frequency window (0.125–1.25 Hz). |
| |
Keywords: | Equilibrium surface tension critical micellar concentration dynamic surface tension surface dilatational elasticity nonionic fluorinated surfactants |
|
|