Acid-base equilibria of weak polyelectrolytes in multilayer thin films
Acid-base equilibria of weak polyelectrolytes in multilayer thin films
复制标题
DOI：
10.1021/la026500i
复制
发表时间：
2003-04-15
期刊：
影响因子：
3.9
通讯作者：
Barrett, CJ
中科院分区：
文献类型：
--
作者：
Burke, SE;Barrett, CJ
在本文中，我们报告的局部表观离解常数的聚（丙烯酸）和聚（烯丙基胺盐酸盐）纳入多层膜的多层薄膜。我们组装了10个表面层的胶态二氧化硅上的顺序静电吸附的聚酸和聚碱的水溶液在不同的pH值，然后测量zeta电位作为溶液pH值的函数，以确定pK（a（app））的每个表面层。结果表明，吸附后的解离常数降低聚（丙烯酸）和增加的情况下，聚（烯丙基胺盐酸盐）。这些偏离理想的行为可以是实质性的，改变多达4个pH单位，并且随着吸附层数量的增加，变化变得更加明显。此外，我们发现，这些pK（a（app））位移的影响，用于组装薄膜的溶液的pH值，但显示在组装浴中使用的盐浓度的依赖性很小。
In this paper, we report on the local apparent dissociation constants of poly(acrylic acid) and poly(allylamine hydrochloride) incorporated in polyelectrolyte multilayer thin films. We assembled 10 polyelectrolyte layers on colloidal silica by the sequential electrostatic adsorption of the polyacid and polybase from aqueous solutions at different pH values and then measured the zeta potential as a function of the solution pH to determine the pK(a(app)) of each surface layer. The results suggest that the dissociation constant decreases upon adsorption for poly(acrylic acid) and increases in the case of poly(allylamine hydrochloride). These deviations from ideal behavior can be substantial, changing by as much as 4 pH units, and the shifts become more pronounced as the number of adsorbed layers increases. In addition, we found that these pK(a(app)) shifts are influenced by the pH of the solution used to assemble the thin films but show little dependence on the salt concentration used in the assembly baths.