刺激响应性混合聚电解质刷的原位红外椭偏光谱研究

In situ infrared ellipsometric study of stimuli-responsive mixed polyelectrolyte brushes.

作者信息

Mikhaylova Yulia, Ionov Leonid, Rappich Jörg, Gensch Michael, Esser Norbert, Minko Sergiy, Eichhorn Klaus-Jochen, Stamm Manfred, Hinrichs Karsten

机构信息

ISAS-Institute for Analytical Sciences, Department Berlin, Albert-Einstein-Strasse 9, 12489 Berlin, Germany.

出版信息

Anal Chem. 2007 Oct 15;79(20):7676-82. doi: 10.1021/ac070853a. Epub 2007 Sep 19.

DOI:10.1021/ac070853a

PMID:17877422

Abstract

The switching behavior of stimuli-responsive mixed polymer brushes (d = 11 nm) was monitored for the first time in liquid phase in situ by infrared spectroscopic ellipsometry (IRSE). IRSE is presented as a new, sensitive in situ tool for online analysis of chemical changes in a thin complex film at the solid/liquid interface. Responsive behavior (protonation and deprotonation reaction) of the poly(acrylic acid)/poly(2-vinylpyridine) (PAA-mix-P2VP) brush was probed in aqueous solutions with pH ranging from pH 2 to pH 10. Structural and chemical changes in a thin polymer brush layer were identified from the analysis of infrared ellipsometric tanPsi spectra during the variation of pH. Systematic change in pH confirmed the reversible switching behavior of the PAA-mix-P2VP brush between three different states: swollen P2VP and compact PAA chains at pH 2, a compact "P2VP...PAA" complex at pH 6.5, and swollen PAA and compact P2VP chains at pH 10.

摘要

首次通过红外光谱椭偏仪（IRSE）在液相中原位监测了刺激响应性混合聚合物刷（d = 11纳米）的开关行为。IRSE作为一种新型的、灵敏的原位工具，用于在线分析固/液界面处薄复合膜中的化学变化。在pH值范围为2至10的水溶液中探测了聚（丙烯酸）/聚（2-乙烯基吡啶）（PAA-mix-P2VP）刷的响应行为（质子化和去质子化反应）。通过在pH值变化期间对红外椭偏tanPsi光谱的分析，确定了聚合物刷薄层中的结构和化学变化。pH值的系统变化证实了PAA-mix-P2VP刷在三种不同状态之间的可逆开关行为：在pH 2时为溶胀的P2VP和致密的PAA链，在pH 6.5时为致密的“P2VP...PAA”复合物，以及在pH 10时为溶胀的PAA和致密的P2VP链。