Institute of Physical Chemistry, Graz University of Technology , Stremayrgasse 9, Graz 8010, Austria.
J Phys Chem A. 2013 Sep 12;117(36):8873-82. doi: 10.1021/jp4046462. Epub 2013 Sep 3.
A comprehensive study of photodegradation processes in optical sensing materials caused by photosensitized singlet oxygen in different polymers is presented. The stabilities of the polymers are accessed in the oxygen consumption measurements performed with help of optical oxygen sensors. Polystyrene and poly(phenylsilesquioxane) are found to be the most stable among the polymers investigated, whereas poly(2,6-dimethyl-p-phenylene oxide) and particularly poly(methyl methacrylate) and their derivatives show the fastest oxygen consumption. The effect of the stabilizers (singlet oxygen quenchers) on the oxygen consumption rates, the photostability of the sensitizer, and the total photon emission (TPE) by singlet oxygen is studied. 1,4-Diazabicyclo[2.2.2]octane (DABCO) was found to significantly reduce both the TPE and the oxygen consumption rates, indicating its role as a physical quencher of singlet oxygen. The addition of DABCO also significantly improved the photostability of the sensitizer. The N-alkylated derivative of DABCO and DABCO covalently grafted to the polystyrene backbone are prepared in an attempt to overcome the volatility and water solubility of the quencher. These derivatives as well as other tertiary amines investigated were found to be inefficient as stabilizing agents, and some of them even negatively affected the oxygen consumption rates.
本文全面研究了不同聚合物中光敏单线态氧引起的光学传感材料光降解过程。通过使用光学氧传感器进行的耗氧测量来评估聚合物的稳定性。研究发现，聚苯乙烯和聚（苯基硅倍半氧烷）是所有研究聚合物中最稳定的，而聚（2,6-二甲基-对-苯撑氧化物），特别是聚甲基丙烯酸甲酯及其衍生物的耗氧速率最快。研究了稳定剂（单线态氧猝灭剂）对耗氧速率、敏化剂的光稳定性以及单线态氧的总光子发射（TPE）的影响。1,4-二氮杂二环[2.2.2]辛烷（DABCO）被发现可显著降低 TPE 和耗氧速率，表明其作为单线态氧的物理猝灭剂的作用。DABCO 的添加还显著提高了敏化剂的光稳定性。DABCO 的 N-烷基化衍生物和共价接枝到聚苯乙烯主链上的 DABCO 被制备，以试图克服猝灭剂的挥发性和水溶性。这些衍生物以及研究的其他叔胺被发现作为稳定剂效率低下，其中一些甚至对耗氧速率产生负面影响。
