Abstract
The rheological properties of micellar aqueous solutions of hydrophobically modified ethylene glycol oligomer, poly(ethylene glycol) monododecyl ether (C12E25), have been studied over a wide range of concentration and temperature. The micellar solution of C12E25 exhibits a sol‐gel transition accompanied by a disorder‐to‐order transition of micelle particles. The following conclusions were made: (1) The sol solution behaves like an ordinary viscous liquid of Newtonian flow, presenting no sign of any change in associations. (2) Under shear deformation, the gel exhibits a yield point around the strain of a few per cent, followed by a plastic flow with further deformation. The plastic flow exhibits a strong non‐Newtonian flow. (3) As the shear rate increases, the sol‐gel transition temperature, observed by steady‐flow viscosity, becomes lower with a reduced sharpness of transition. (4) The long‐range structural order of the lattice in the gel, destroyed by the plastic flow, is suggested to substantially recover in 10–100 s.
Concentration dependency on the steady‐flow viscosity at the shear rate of 10 s^−1^ for C12E25 aqueous solutions at 70 °C. The inset shows the linear–linear plots.
magnified imageConcentration dependency on the steady‐flow viscosity at the shear rate of 10 s^−1^ for C12E25 aqueous solutions at 70 °C. The inset shows the linear–linear plots.