Association between Nonionic Amphiphilic Polymer and Ionic Surfactant in Aqueous Solutions: Effect of Polymer Hydrophobicity and Micellization
Association between Nonionic Amphiphilic Polymer and Ionic Surfactant in Aqueous Solutions: Effect of Polymer Hydrophobicity and Micellization
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DOI：
10.3390/polym12081831
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发表时间：
2020-08-01
期刊：
影响因子：
5
通讯作者：
Alexandridis, Paschalis
中科院分区：
文献类型：
--
作者：
Kancharla, Samhitha;Zoyhofski, Nathan A.;Alexandridis, Paschalis
表面活性剂与两亲聚合物在水溶液中的相互作用可能比表面活性剂与均聚物的相互作用更复杂。利用多种实验技术研究了常见的离子型表面活性剂十二烷基硫酸钠（SDS）与聚环氧乙烷-聚环氧丙烷-聚环氧乙烷（PEO-PPO-PEO）型非离子型两亲聚合物之间的相互作用。本文研究的聚合物两亲物是Pluronic F127（EO 100 PO 65 EO 100）和Pluronic P123（EO 19 PO 69 EO 19），具有相同长度的PPO嵌段，但不同长度的PEO嵌段，因此，非常不同的临界胶束化浓度（CMC）。在固定聚合物含量的水溶液中，随着表面活性剂浓度的增加，SDS与未缔合的PEO-PPO-PEO分子相互作用，首先形成富含SDS的SDS/Pluronic组装体，然后形成自由SDS胶束。SDS与胶束化的PEO-PPO-PEO相互作用以形成富含Pluronic的SDS/Pluronic组装体，其在表面活性剂浓度进一步增加时分解并转变成富含SDS的SDS/Pluronic组装体，随后形成游离SDS胶束。富含SDS的SDS/Pluronic组装体表现出疏水特性。非离子型大分子两亲物和短链离子型两亲物之间的相互作用和缔合方式受聚合物的疏水性及其在水溶液中的浓度的影响。例如，当与Pluronic P123胶束（类似于ImM）相比时，SDS以低得多的浓度（类似于0.OlmM）结合Pluronic F127胶束。SDS在PEO-PPO-PEO水溶液中的临界缔合浓度（CAC）远低于在PEO均聚物水溶液中的CAC。
The interaction in aqueous solutions of surfactants with amphiphilic polymers can be more complex than the surfactant interactions with homopolymers. Interactions between the common ionic surfactant sodium dodecyl sulfate (SDS) and nonionic amphiphilic polymers of the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) type have been probed utilizing a variety of experimental techniques. The polymer amphiphiles studied here are Pluronic F127 (EO100PO65EO100) and Pluronic P123 (EO19PO69EO19), having the same length PPO block but different length PEO blocks and, accordingly, very different critical micellization concentrations (CMC). With increasing surfactant concentration in aqueous solutions of fixed polymer content, SDS interacts with unassociated PEO-PPO-PEO molecules to first form SDS-rich SDS/Pluronic assemblies and then free SDS micelles. SDS interacts with micellized PEO-PPO-PEO to form Pluronic-rich SDS/Pluronic assemblies, which upon further increase in surfactant concentration, break down and transition into SDS-rich SDS/Pluronic assemblies, followed by free SDS micelle formation. The SDS-rich SDS/Pluronic assemblies exhibit polyelectrolyte characteristics. The interactions and mode of association between nonionic macromolecular amphiphiles and short-chain ionic amphiphiles are affected by the polymer hydrophobicity and its concentration in the aqueous solution. For example, SDS binds to Pluronic F127 micelles at much lower concentrations (similar to 0.01 mM) when compared to Pluronic P123 micelles (similar to 1 mM). The critical association concentration (CAC) values of SDS in aqueous PEO-PPO-PEO solutions are much lower than CAC in aqueous PEO homopolymer solutions.