Key Laboratory of Colloid and Interface Chemistry, Shandong University, Jinan 250100, China.
J Colloid Interface Sci. 2012 Nov 15;386(1):205-11. doi: 10.1016/j.jcis.2012.07.026. Epub 2012 Jul 20.
Coarse-grained molecular dynamics simulations have been performed to study the self-assembly of polymer, polyacrylamide (PAM) and surfactant, sodium dodecylsulfate (SDS) in aqueous solution. Our simulations revealed that PAM curled into clusters in the absence of SDS, while it was stretched if SDS was added. For the SDS-PAM complexes, the aggregate formation process can be divided into three stages: firstly, PAM quickly absorbs some SDS monomers until the radius of gyration (Rg) of polymer reaches a minimum; then, PAM stretches and the Rg of PAM increases due to more and more adsorbed SDS; ultimately, the commonly accepted "necklace" structure is formed with PAM located at the interface of the hydrophobic and hydrophilic regions of the SDS micelle. The main driving force for the association was hydrophobic interactions between the polymer backbone and the surfactant hydrophobic tails. As the concentration of SDS increased, the Rg of PAM increased up to a maximum, indicating the polymer was saturated with surfactant.
我们进行了粗粒化分子动力学模拟，以研究聚合物聚丙烯酰胺（PAM）和表面活性剂十二烷基硫酸钠（SDS）在水溶液中的自组装。我们的模拟表明，在没有 SDS 的情况下，PAM 卷曲成簇，而加入 SDS 后则伸展。对于 SDS-PAM 复合物，聚集形成过程可以分为三个阶段：首先，PAM 迅速吸收一些 SDS 单体，直到聚合物的回转半径（Rg）达到最小值；然后，由于吸附的 SDS 越来越多，PAM 伸展，Rg 增加；最终，形成了公认的“项链”结构，PAM 位于 SDS 胶束亲水区和疏水区的界面处。聚合物主链与表面活性剂疏水尾之间的疏水相互作用是缔合的主要驱动力。随着 SDS 浓度的增加，PAM 的 Rg 增加到最大值，表明聚合物与表面活性剂达到饱和。
