Tuning the pH sensitivity of poly(methacrylic acid) brushes.
Tuning the pH sensitivity of poly(methacrylic acid) brushes.
复制标题
DOI：
10.1021/la200347u
复制
发表时间：
2011-03
期刊：
影响因子：
--
通讯作者：
Nicolas Schüwer;H. Klok
中科院分区：
文献类型：
--
作者：
Nicolas Schüwer;H. Klok
PH引起的表面束缚的弱聚电解质刷子的膨胀和坍塌对于开发致动器或允许pH控制的传输或吸附是有意义的。这篇文章讨论了一系列广泛的石英晶体微天平(QCM)实验的结果，这些实验旨在(I)进一步了解刷子厚度和密度对聚甲基丙烯酸(PMAA)刷子pH响应性的影响，以及(Ii)开发允许人们设计基于PMAA的刷子的pH响应性和动态响应范围的策略。结果表明，由于其较高的接枝密度，表面连结的PMAA在溶液中的表观pK(A)不同于相应的游离聚合物，并且覆盖了较宽的pH范围。PMAA刷子的pK(A)取决于刷子的厚度和密度；刷子越厚，pK(A)值越高，越高的密度刷子开始膨胀。论文的第二部分论证了N-羟基琥珀酰亚胺介导的聚合后修饰用于工程PMAA刷子的pH响应性的可行性。通过使用适当的胺基官能化酸，可以调节这些PMAA基聚电解质刷子的最大响应pH和动态响应范围。
The pH-induced swelling and collapse of surface-tethered, weak polyelectrolyte brushes is of interest for the development of actuators or to allow pH controlled transport or adsorption. This contribution discusses results of an extensive series of quartz crystal microbalance (QCM) experiments that aimed at (i) further understanding the influence of brush thickness and density on the pH responsiveness of poly(methacrylic acid) (PMAA) brushes and (ii) developing strategies that allow one to engineer the pH responsiveness and dynamic response range of PMAA based brushes. It was observed that, due to their high grafting density, the apparent pK(a) of surface-tethered PMAA differs from that of the corresponding free polymer in solution and also covers a broader pH range. The pK(a) of the PMAA brushes was found to depend on both brush thickness and density; thicker brushes showed a higher pK(a) value, and brushes of higher density started to swell at higher pH. The second part of the paper demonstrates the feasibility of the N-hydroxysuccinimide-mediated post-polymerization modification to engineer the pH responsiveness of the PMAA brushes. By using appropriate amine functionalized acids, it was possible to tune both the pH of maximum response as well as the dynamic response range of these PMAA based polyelectrolyte brushes.