Tailoring the charge density of surface-attached polyelectrolyte brushes
Tailoring the charge density of surface-attached polyelectrolyte brushes
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DOI：
10.1021/ma035425v
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发表时间：
2004-03-23
期刊：
影响因子：
5.5
通讯作者：
Rühe, J
中科院分区：
文献类型：
--
作者：
Biesalski, M;Rühe, J
介绍了表面附着荷电统计共聚物刷的制备及其溶胀行为。刷的制备通过自由基链聚合的单体混合物的4-乙烯基吡啶（VP）和二甲基丙烯酰胺（DMAA）使用表面结合的偶氮引发剂（表面引发聚合）。然后将如此制备的中性PVP-stat-PDMMA共聚物刷通过相应PVP链段的聚合物类似的季铵化反应转移到无规刷中。通过调节添加到聚合进料中的单体的比例，可以控制在最终表面附着层中产生的相应聚合物链段的浓度，因此，可以确定所得嵌段共聚物刷的电荷密度。最后，用多角度消光椭圆偏振法研究了这种刷在低分子盐水溶液中的溶胀行为。取决于共聚物的电荷密度，刷表现出介于中性聚合物刷和聚合物刷之间的溶胀行为。因此，可以精确地控制层对周围介质中存在的盐的敏感性。
The preparation and swelling behavior of surface-attached charged statistical copolymer brushes are described. The brushes are prepared by free radical chain polymerization of monomer mixtures of 4-vinylpyridine (VP) and dimethylacrylamide (DMAA) using a surface bound azo-initiator (surface-initiated polymerization). So-prepared neutral PVP-stat-PDMMA copolymer brushes are then transferred into polyelectrolyte brushes through a polymer-analogous quaternization reaction of the respective PVP segments. By adjusting the ratio of the monomers added to the polymerization feed, the concentration of the corresponding polymer segments generated in the final surface-attached layer can be controlled, and thus, the charge density of the resulting polyelectrolyte copolymer brush can be determined. Finally, the swelling behavior of such polyelectrolyte brushes in aqueous solutions containing low molecular weight salts is investigated by using multiple-angle null ellipsometry. Depending on the charge density of the copolymers, the brushes exhibit a swelling behavior between that of a polyelectrolyte and a neutral polymer brush. Thus, the sensitivity of the layers against salt present in the surrounding medium can be precisely controlled.