疏水缔合聚丙烯酸与蠕虫状胶束的协同作用

Synergism between Hydrophobically Modified Polyacrylic Acid and Wormlike Micelles

从宏观流变性和介观尺度方面,研究了疏水缔合聚丙烯酸(HMPA)与油酸钠(NaOA)构筑的蠕虫状胶束的协同作用.考察HMPA对蠕虫状胶束溶液流变性和表观粘度的影响,结果表明,极少量HMPA的引入导致蠕虫状胶束溶液体系动态模量明显增加;其表观粘度随HMPA浓度的增加先增强后减弱.另一方面,通过耗散颗粒动力学(DPD)分子模拟方法研究了混合体系中溶液组成对HMPA分子链的均方根末端距的影响.结果表明,随着NaOA浓度增加,HMPA的均方根末端距会出现峰值;HMPA的伸展程度受其自身浓度变化制约,相对于纯HMPA体系,NaOA胶束的存在对高浓度区的HMPA伸展程度影响更明显.结合流变实验和分子模拟结果,初步解释了聚合物与蠕虫状胶束的协同作用机制.

The synergism between wormlike micelles formed from sodium oleate （NaOA） and hydrophobically modified polyacrylic acid （HMPA） was investigated according to their macroscopic performances and mesoscopic scales, using a combination of viscosity/rheology measurements and dissipative particle dynamics （DPD） molecular simulations. The rheology of NaOA wormlike micelles changed significantly following the addition of a small amount of HMPA, which verified the synergistic effect between them. A peak in the apparent viscosity was observed following an increase in the concentration of HMPA, suggesting that the synergistic effect was restricted by the composition of the mixture. A DPD simulation also confirmed that the solution composition had an influence on the root mean square （RMS） end-to-end distances of HMPA, with the observed value fluctuating according to NaOA and HMPA concentrations. The micellar morphology affected the RMS end-to-end distances of HMPA and the presence of NaOA micelles exerted a significant impact on the extension of HMPA at high HMPA concentrations. A proposed synergistic mechanism has been presented according to the experimental and simulation results.