Poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA) is a pH-sensitive polymer, while a few recent studies have shown it to possess temperature responsiveness as well. In this article, poly(2-(diethylamino)ethyl methacrylate-co-2,2,6,6-tetramethyl-4-piperidyl methacrylate)s, DEA-TMPMs, were synthesized. The TMPM moieties in DEA-TMPMs were subsequently oxidized with hydrogen peroxide to obtain poly(2-(diethylamino)ethyl methacrylate-co-2,2,6,6-tetramethylpiperidine-1-oxyl methacrylate), DEA-TMPs, having nitroxide radicals on the polymer chains. DEA-TMPMs were characterized by nuclear magnetic resonance spectroscopy, gel permeation chromatography, differential scanning calorimetry and thermogravimetry techniques, whereas DEA-TMPs were analyzed by Fourier transform infrared spectroscopy, cyclic voltammetry, and electron paramagnetic resonance (EPR) spectroscopy. The results showed that at low pH, the rotational mobility of nitroxide radicals was reduced as EPR spectra mostly consisted of slow-motion component. This slow-motion component in the EPR spectra remained unchanged below neutral pH. These results indicated a sort of interaction among nitroxide radicals and protonated amine groups of DEAEMA monomers.

中文翻译：

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聚(甲基丙烯酸二乙氨基乙酯-co-2,2,6,6-四甲基-4-哌啶基甲基丙烯酸酯)的合成及其链段运动研究

聚（2-（二乙基氨基）甲基丙烯酸乙酯）（PDEAEMA）是一种对 pH 值敏感的聚合物，而最近的一些研究表明它也具有温度响应性。在本文中，合成了聚（2-（二乙氨基）甲基丙烯酸乙酯-co-2,2,6,6-四甲基-4-哌啶基甲基丙烯酸酯），DEA-TMPMs。DEA-TMPMs 中的 TMPM 部分随后用过氧化氢氧化得到聚（2-（二乙氨基）乙基甲基丙烯酸酯-co-2,2,6,6-四甲基哌啶-1-甲基丙烯酸酯），DEA-TMPs，具有氮氧自由基在聚合物链上。DEA-TMPMs 通过核磁共振光谱、凝胶渗透色谱、差示扫描量热法和热重分析技术进行表征，而 DEA-TMPs 通过傅里叶变换红外光谱、循环伏安法、和电子顺磁共振（EPR）光谱。结果表明，在低pH值下，由于EPR光谱主要由慢运动成分组成，氮氧自由基的旋转迁移率降低。EPR 光谱中的这种慢动作分量在中性 pH 值以下保持不变。这些结果表明氮氧自由基和 DEAEMA 单体的质子化胺基之间存在某种相互作用。