In the present paper,a structure-based viscoelastic model is employed to characterize and predict the viscoelastic properties of a wormlike micellar solution at 20℃.Considering the effect of shear rate on linear visc...In the present paper,a structure-based viscoelastic model is employed to characterize and predict the viscoelastic properties of a wormlike micellar solution at 20℃.Considering the effect of shear rate on linear viscoelastic property,a structural parameter f is obtained.Meanwhile,another structural parameterζis determined when the effects of time and shear rate are considered simultaneously.Both structural parameters are calculated by using linear interpolation method.The startup experiment can be described well by the model.The prediction on the shear stress in the ramping-up region of the hysteresis loop experiment shows an apparent relation between the rheological behaviors in the startup experiment and those in the hysteresis loop experiment.For the hysteresis loop experiment with 30 s time interval,the defect of the calculation in 0.001-0.01 s^(−1) is due to the lack of the ramping-down history effect.In addition,the model can improve completeness of perimental data used for characterizing rheological property.展开更多
Spin-lattice relaxation time, spin-spin relaxation time and two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOESY) experiments of polyoxyethylene lauryl ether (Brij-35) micelles in aqueous solutions at...Spin-lattice relaxation time, spin-spin relaxation time and two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOESY) experiments of polyoxyethylene lauryl ether (Brij-35) micelles in aqueous solutions at a concentration of 100 times the critical micellar concentration (cmc) give direct evidence that the hydrophilic polyoxyethylene chains, staying in the exterior of the micellar core, are coiled, bent and aligned around the micellar core with a certain number of water molecules included. This hydrophilic layer is in contact with the solvent, water, keeping the micellar solution stable. 1H NMR relaxation time measurements show that the first oxyethylene group next to the alkyl chain participates in the formation of the surface area of the micellar core. The motion of the hydrophilic polyoxyethylene chains is less restricted as compared with the hydrophobic alkyl chains.展开更多
文摘In the present paper,a structure-based viscoelastic model is employed to characterize and predict the viscoelastic properties of a wormlike micellar solution at 20℃.Considering the effect of shear rate on linear viscoelastic property,a structural parameter f is obtained.Meanwhile,another structural parameterζis determined when the effects of time and shear rate are considered simultaneously.Both structural parameters are calculated by using linear interpolation method.The startup experiment can be described well by the model.The prediction on the shear stress in the ramping-up region of the hysteresis loop experiment shows an apparent relation between the rheological behaviors in the startup experiment and those in the hysteresis loop experiment.For the hysteresis loop experiment with 30 s time interval,the defect of the calculation in 0.001-0.01 s^(−1) is due to the lack of the ramping-down history effect.In addition,the model can improve completeness of perimental data used for characterizing rheological property.
基金This work was supported by the National Key Basic Research Development Program "Fundamental Studies of the Extensively Enhanced Petroleum Recovery" (Grant No. G199022504) .
文摘Spin-lattice relaxation time, spin-spin relaxation time and two-dimensional nuclear Overhauser enhancement spectroscopy (2D NOESY) experiments of polyoxyethylene lauryl ether (Brij-35) micelles in aqueous solutions at a concentration of 100 times the critical micellar concentration (cmc) give direct evidence that the hydrophilic polyoxyethylene chains, staying in the exterior of the micellar core, are coiled, bent and aligned around the micellar core with a certain number of water molecules included. This hydrophilic layer is in contact with the solvent, water, keeping the micellar solution stable. 1H NMR relaxation time measurements show that the first oxyethylene group next to the alkyl chain participates in the formation of the surface area of the micellar core. The motion of the hydrophilic polyoxyethylene chains is less restricted as compared with the hydrophobic alkyl chains.
