• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文会议>Macromolecular Symposia 211; Dresden Polymer Discussion: Polyelectrolytes; 20030316-19; Dresden(DE) >Aggregation Phenomena in Polyelectrolyte Multilayers Made from Polyelectrolytes Bearing Bulky Functional, Hydrophobic Fragments
【24h】

Aggregation Phenomena in Polyelectrolyte Multilayers Made from Polyelectrolytes Bearing Bulky Functional, Hydrophobic Fragments

机译：由带有庞大的功能性，疏水性片段的聚电解质制成的聚电解质多层中的聚集现象

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The functionalization of polyelectrolyte multilayers often implies the use of bulky functional fragments, attached to a standard polyelectrolyte matrix. Despite of the high density of non-charged, often hydrophobic substituents, regular film growth by sequential adsorption proceeds easily when an appropriate polyelectrolyte counter ion is chosen. However, the functional fragments may cluster or aggregate. This complication is particularly evident when using chromophores and fluorophores as bulky pendant groups. Attention has to be paid to this phenomenon for the design of functional polyelectrolyte films, as aggregation may modify crucially the properties. The use of charged spacer groups does not necessarily suppress the aggregation of functional side groups. Still, clustering and aggregation depend on the detailed system employed, and are not obligatory. In the case of cationic poly(acrylamide)s labeled with naphthalene and pyrene fluorophores, for instance, the polymers form intramolecular hydrophobic associates in solution, as indicated by strong excimer formation. But the polymers can undergo a conformational rearrangement upon adsorption so that they are decoiled in the adsorbed films. Analogous observations are made for polyanions bearing mesogenic biphenyls fragments. In contrast, polycations functionalized with the dye coumarin 343 show little aggregation in solution, but a marked aggregation in the ESA films.
机译：聚电解质多层的功能化通常意味着使用附接到标准聚电解质基质上的庞大功能片段。尽管不带电荷的，通常是疏水性的取代基具有很高的密度，但是当选择合适的聚电解质抗衡离子时，通过顺序吸附进行规则的膜生长仍很容易进行。但是，功能片段可能会聚集或聚集。当使用发色团和荧光团作为庞大的侧基时，这种并发症尤为明显。功能聚电解质薄膜的设计必须注意这种现象，因为聚集可能会严重影响其性能。带电间隔基的使用不一定抑制官能侧基的聚集。集群和聚合仍然取决于所采用的详细系统，并非必须的。例如，在用萘和pyr荧光团标记的阳离子聚（丙烯酰胺）的情况下，聚合物会在溶液中形成分子内疏水性缔合体，这表现为强烈的准分子形成。但是，聚合物在吸附时会发生构象重排，从而使它们在吸附的膜中脱脂。对带有介晶联苯片段的聚阴离子进行了类似的观察。相反，用染料香豆素343官能化的聚阳离子在溶液中几乎没有聚集，但在ESA膜中聚集明显。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号