粘度对聚合物共混物相分离动力学的影响研究

模拟了粘度反差二元流体混合物的相分离,考察了粘度对相分离动力学的影响,发现相区域的增长主要由粘度较大的组分所控制,合理地解释了粘度效应所导致的一些实验现象.证明了即使组分间的粘度比很大,也没有出现反转相结构,说明在不施加剪切流场情况下,粘度反差不是形成反转相的原因.

Studies on Viscosity Effects on Phase Separation Dynamics of Polymer Mixtures

The simulation on the phase separations of binary fluids with the same and different viscosities has been done and the viscosity effects on the dynamics of phase separations are considered. We found that the domain growth exponent is controlled by the more viscouse phase in the on-critical cases. It reveals that the domain growth at the late stage is dominated by the component with a larger viscosity, which could be used to properly explain some experimental phenomena resulted from the viscosity effects. In off-critical cases, the growth exponent is the characteristic exponent of 1/3. It can be explained by the mechanism of droplet coalescene at the late stage of phase separation in an off-critical binary mixture. It is also demonstrated that in the absence of shear flow, the viscosity difference is not the reason for the inversed phase structure since no inversed phase structure has emerged during the phase separations in our simulation, even if the differences between the two components′ viscosities are very large.