Westfälische Wilhelms-Universität Münster, Correnstrasse 40, 48149 Münster, Germany.
Langmuir. 2013 May 28;29(21):6369-76. doi: 10.1021/la401179s. Epub 2013 May 15.
The preparation of polymer brushes (PBs) bearing α-hydroxyalkylphenylketone (2-hydroxy-2-methyl-1-phenylpropan-1-one) moieties as photoreactive polymer backbone substituents is presented. Photoreactive polymer brushes with defined thicknesses (up to 60 nm) and high grafting densities are readily prepared by surface initiated nitroxide mediated radical polymerization (SINMP). The photoactive moieties can be transformed via Norrish-type I photoreaction to surface-bound acyl radicals. Photolysis in the presence of a persistent nitroxide leads to chemically modified PBs bearing acylalkoxyamine moieties as side chains resulting from trapping of the photogenerated acyl radicals with nitroxides. Application of functionalized nitroxides to the photochemical PB postmodification provides functionalized PBs bearing cyano, polyethylene glycol (PEG), perfluoroalkyl, and biotin moieties. As shown for one case, photochemical postfunctionalization of the PB through a mask using a biotin-conjugated nitroxide as the trapping reagent leads to the corresponding site-selective chemically modified PB, which is successfully used for site-specific streptavidin immobilization. Surface analysis of PBs was performed by contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), attenuated total reflection (ATR), fourier transform infrared (FTIR) spectroscopy, and fluorescence microscopy.
本文介绍了一种将含有α-羟烷基苯甲酮（2-羟基-2-甲基-1-苯基-1-丙酮）部分的聚合物刷（PBs）作为光反应性聚合物主链取代基的制备方法。通过表面引发氮氧自由基介导的自由基聚合（SINMP），可以容易地制备具有确定厚度（高达 60nm）和高接枝密度的光反应性聚合物刷。光活性部分可以通过 Norrish 型 I 光反应转化为表面结合的酰基自由基。在持久氮氧自由基存在下的光解导致具有酰基烷氧基胺侧链的化学修饰 PB，这是由于光生成的酰基自由基与氮氧自由基的捕获而产生的。将功能化的氮氧自由基应用于光化学 PB 后修饰提供了带有氰基、聚乙二醇（PEG）、全氟烷基和生物素部分的功能化 PB。如一个案例所示，通过使用作为捕获试剂的生物素化氮氧自由基对 PB 进行掩蔽后的光化学后修饰，导致相应的位点选择性化学修饰 PB，成功地用于位点特异性链霉亲和素固定化。通过接触角（CA）测量、X 射线光电子能谱（XPS）、衰减全反射（ATR）、傅里叶变换红外（FTIR）光谱和荧光显微镜对 PB 进行了表面分析。
