Liu Dongjie, Li Yong, Liu Fei, Zhou Wenjing, Sun Ansu, Liu Xiaoteng, Chen Fei, Xu Ben Bin, Wei Jinjia
School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, China.
State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an 710049, China.
Polymers (Basel). 2020 Jan 25;12(2):265. doi: 10.3390/polym12020265.
Interfacial interactions within a multi-phase polymer solution play critical roles in processing control and mass transportation in chemical engineering. However, the understandings of these roles remain unexplored due to the complexity of the system. In this study, we used an efficient analytical method-a nonequilibrium molecular dynamics (NEMD) simulation-to unveil the molecular interactions and rheology of a multiphase solution containing cetyltrimethyl ammonium chloride (CTAC), polyacrylamide (PAM), and sodium salicylate (NaSal). The associated macroscopic rheological characteristics and shear viscosity of the polymer/surfactant solution were investigated, where the computational results agreed well with the experimental data. The relation between the characteristic time and shear rate was consistent with the power law. By simulating the shear viscosity of the polymer/surfactant solution, we found that the phase transition of micelles within the mixture led to a non-monotonic increase in the viscosity of the mixed solution with the increase in concentration of CTAC or PAM. We expect this optimized molecular dynamic approach to advance the current understanding on chemical-physical interactions within polymer/surfactant mixtures at the molecular level and enable emerging engineering solutions.
多相聚合物溶液中的界面相互作用在化学工程的过程控制和质量传输中起着关键作用。然而，由于系统的复杂性，对这些作用的理解仍未得到探索。在本研究中，我们使用了一种高效的分析方法——非平衡分子动力学（NEMD）模拟——来揭示含有十六烷基三甲基氯化铵（CTAC）、聚丙烯酰胺（PAM）和水杨酸钠（NaSal）的多相溶液的分子相互作用和流变学。研究了聚合物/表面活性剂溶液相关的宏观流变特性和剪切粘度，计算结果与实验数据吻合良好。特征时间与剪切速率之间的关系符合幂律。通过模拟聚合物/表面活性剂溶液的剪切粘度，我们发现混合物中胶束的相变导致混合溶液的粘度随着CTAC或PAM浓度的增加而非单调增加。我们期望这种优化的分子动力学方法能够在分子水平上推进当前对聚合物/表面活性剂混合物中化学物理相互作用的理解，并实现新出现的工程解决方案。
