Experimental study on microrheological properties of polyethylene oxide solution based on single particle tracking method

The microrheological properties of polyethylene oxide (PEO) solution under different temperatures and different concentrations were studied based on the single particle tracking (SPT) method in this paper. Based on the generalized Stokes-Einstein relationship and the viscoelastic theory of complex fluid, the microrheological properties of PEO dilute solution with concentration of 0.4 wt%~1.0 wt% at 25℃, 35℃ and 45℃ were measured and analyzed by the particle tracking technique. The study results show that the restriction of Brownian motion of the probe particles increases with the increase of the solution concentration. The Brownian motion is most restricted under the concentration of 1.0 wt% and the temperature of 25℃. The solved results of the viscoelastic modulus show that PEO solution is a complex fluid with dominant viscous modulus and weak elastic modulus under the experimental conditions. The viscoelastic modulus of the solution increases with the increase of the solution concentration under the same temperature. Both the elastic modulus (G'(ω)) and the viscous modulus (G"(ω)) show the decreasing trend with the increase of the temperature, and the decreasing rate of the elastic modulus is larger than that of the viscous modulus. The analysis of MSD standard deviation indicates that the measurement errors show the increasing trend with the increase of the tracking time in the microrheological experiment based on SPT method.