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Effects of Ionic Strength and Ion Specificity on the Interface Behavior of Poly(dimethylaminoethyl methacrylate)–Poly(lauryl methacrylate)
Langmuir ( IF 3.7 ) Pub Date : 2021-02-11 , DOI: 10.1021/acs.langmuir.0c03424
Hongxu Chen 1 , Gangyao Wen 1 , Varvara Chrysostomou 2 , Stergios Pispas 2 , Hongfei Li 3 , Zhaoyan Sun 3
Affiliation  

The ion specificity effect on the water solubility of poly(N-isopropylacrylamide)-containing copolymers complies with the Hofmeister series, which is applicable to other copolymers or not need to be explored. In this work, effects of ionic strength under acidic conditions and ion specificity under alkaline conditions on the air/water interface behavior of two amphiphilic diblock copolymers poly(dimethylaminoethyl methacrylate)–poly(lauryl methacrylate) (PDMAEMA-PLMA) were systematically studied. Under acidic conditions, the surface pressure–area isotherms of a predominantly hydrophilic copolymer are insensitive to ionic strength. In contrast, the isotherms of a predominantly hydrophobic copolymer successively shift to the large, small, and large molecular area with the increase of ionic strength. Under alkaline conditions, the interfacial stretch degrees of PDMAEMA chains of two copolymers change with salt species and concentrations, which do not comply with the Hofmeister series. All of the Langmuir–Blodgett films of the former copolymer exhibit separate circular micelles. Nevertheless, those of the latter copolymer obtained under alkaline conditions exhibit various distinctive morphologies such as separate circular micelles, large separate PLMA cores within large PDMAEMA domains, and large PLMA domains/aggregates surrounded by short PDMAEMA shells. It can be attributed to the high deformability of PLMA chains, the ion specificity effect on the stretch degree of PDMAEMA blocks, and their underwater solubility upon compression.

中文翻译:

离子强度和离子特异性对聚甲基丙烯酸二甲氨基乙酯-聚甲基丙烯酸月桂酯的界面行为的影响

离子特异性对聚N水溶性的影响含-异丙基丙烯酰胺的共聚物符合Hofmeister系列,该系列适用于其他共聚物或无需探讨。在这项工作中,系统地研究了酸性条件下的离子强度和碱性条件下的离子特异性对两种两亲性二嵌段共聚物聚(甲基丙烯酸二甲氨基乙酯)-聚甲基丙烯酸月桂酯(PDMAEMA-PLMA)的空气/水界面行为的影响。在酸性条件下,主要为亲水性共聚物的表面压力-面积等温线对离子强度不敏感。相反,随着离子强度的增加,主要为疏水性共聚物的等温线相继转移到大,小和大的分子区域。在碱性条件下 两种共聚物的PDMAEMA链的界面拉伸度会随盐的种类和浓度而变化,这与Hofmeister系列不符。前一种共聚物的所有Langmuir-Blodgett膜都显示出单独的圆形胶束。然而,在碱性条件下获得的后一种共聚物的那些表现出各种独特的形态,例如分开的圆形胶束,在大的PDMAEMA结构域内的大的分开的PLMA核,以及被短的PDMAEMA壳包围的大的PLMA结构域/聚集体。这可以归因于PLMA链的高可变形性,离子特异性对PDMAEMA嵌段拉伸度的影响以及它们在压缩时的水下溶解度。前一种共聚物的所有Langmuir-Blodgett膜都显示出单独的圆形胶束。然而,在碱性条件下获得的后一种共聚物的那些表现出各种独特的形态,例如分开的圆形胶束,在大的PDMAEMA结构域内的大的分开的PLMA核,以及被短的PDMAEMA壳包围的大的PLMA结构域/聚集体。这可以归因于PLMA链的高可变形性,离子特异性对PDMAEMA嵌段拉伸度的影响以及它们在压缩时的水下溶解度。前一种共聚物的所有Langmuir-Blodgett膜都显示出单独的圆形胶束。然而,在碱性条件下获得的后一种共聚物的那些表现出各种独特的形态,例如分开的圆形胶束,在大的PDMAEMA结构域内的大的分开的PLMA核,以及被短的PDMAEMA壳包围的大的PLMA结构域/聚集体。这可以归因于PLMA链的高可变形性,离子特异性对PDMAEMA嵌段拉伸度的影响以及它们在压缩时的水下溶解度。以及被短PDMAEMA外壳包围的大型PLMA域/集合。这可以归因于PLMA链的高可变形性,离子特异性对PDMAEMA嵌段拉伸度的影响以及它们在压缩时的水下溶解度。以及被短PDMAEMA外壳包围的大型PLMA域/集合。这可以归因于PLMA链的高可变形性,离子特异性对PDMAEMA嵌段拉伸度的影响以及它们在压缩时的水下溶解度。
更新日期:2021-02-23
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