Influence of pH on the Growth and the Local Dynamics of Polyelectrolyte Multilayers
Influence of pH on the Growth and the Local Dynamics of Polyelectrolyte Multilayers
复制标题
pH 对聚电解质多层膜生长和局部动力学的影响
DOI：
10.1021/acs.macromol.0c01756
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发表时间：
2021
期刊：
影响因子：
5.5
通讯作者：
Lappan
中科院分区：
文献类型：
--
作者：
Scheler;Lappan
采用强阳离子型聚二烯基二甲基氯化铵和弱阴离子型聚乙烯-马来酸盐[P(E-alt-MA)]制备了聚电解质多层膜。将自旋标记物（SL） 4-氨基-2,2,6,6-四甲基哌啶- 1-氧化物共价附着在聚阴离子[SL- p (E-alt-MA)]上，监测信号强度的变化，作为连续波电子顺磁共振光谱获得的层生长和指示聚合物链迁移率的谱线形状的测量指标。本研究的目的是探讨制备条件的影响。我们分别展示了pH值对16层和17层PEMs的形成和迁移率的影响。在第一部分中，利用自旋标记的聚阴离子制备每个聚阴离子层，以监测多层膜的生长情况。在所有pH值为3到6的情况下，在PEM开始形成时，表面尚未完全覆盖，呈现非线性生长行为，在达到过渡点后呈现线性生长。这一点取决于pH值。在第二项研究中，选择性地将自旋标记的聚阴离子放置在一层中，以显示多层中该层中SL的旋转迁移率的变化。结果表明，随着pH值的增加，SL-P（E-alt-MA）的旋转迁移率增加。
Polyelectrolyte multilayers (PEMs) have been prepared using the strong polycation poly(diallyldimethylammonium chloride) and the weak polyanion poly(ethylene-alt-maleic acid) [P(E-alt-MA)]. The spin label (SL) 4-amino-2,2,6,6-tetramethylpiperidine 1-oxide was covalently attached to the polyanion [SL-P(E-alt-MA)] to monitor changes in the signal intensity as a measure of the layer growth and the line shape of the spectra indicative of the polymer chain mobility obtained by continuous wave electron paramagnetic resonance spectroscopy. The aim of this study was to investigate the influence of the preparation conditions. We show the influence of the pH value on the buildup and the mobility of PEMs with 16 and 17 layers, respectively. In the first part, the spin-labeled polyanion was used in the preparation of each polyanion layer to monitor the growth of the multilayers. For all pH values from 3 to 6 a non-linear growth behavior was obtained at the beginning of the PEM buildup where the surface is not yet fully covered, leading to a linear growth after reaching a transition point. This point depends on the pH value. In a second study, the spin-labeled polyanion was selectively placed in one layer to display changes in the rotational mobility of the SL in this layer within the multilayers. As a result, an increase of the rotational mobility of SL-P(E-alt-MA) with increasing pH value was observed.